Computer Misuse Act 1990
A person is guilty of an offence if—
he causes a computer to perform any function with intent to secure access to any program or data held in any computer , or to enable any such access to be secured;
the access he intends to secure , or to enable to be secured, is unauthorised; and
he knows at the time when he causes the computer to perform the function that that is the case.
The intent a person has to have to commit an offence under this section need not be directed at—
any particular program or data;
a program or data of any particular kind; or
a program or data held in any particular computer.
A person guilty of an offence under this section shall be liable—
on summary conviction in England and Wales, to imprisonment for a term not exceeding the general limit in a magistrates’ court or to a fine not exceeding the statutory maximum or to both;
on summary conviction in Scotland, to imprisonment for a term not exceeding 12 months or to a fine not exceeding the statutory maximum or to both;
on conviction on indictment, to imprisonment for a term not exceeding two years or to a fine or to both.
A person is guilty of an offence under this section if he commits an offence under section 1 above (“the unauthorised access offence”) with intent— and the offence he intends to commit or facilitate is referred to below in this section as the further offence.
to commit an offence to which this section applies; or
to facilitate the commission of such an offence (whether by himself or by any other person);
This section applies to offences—
for which the sentence is fixed by law; or
for which a person who has attained the age of twenty-one years (eighteen in relation to England and Wales) and has no previous convictions may be sentenced to imprisonment for a term of five years (or, in England and Wales, might be so sentenced but for the restrictions imposed by section 33 of the Magistrates’ Courts Act 1980).
It is immaterial for the purposes of this section whether the further offence is to be committed on the same occasion as the unauthorised access offence or on any future occasion.
A person may be guilty of an offence under this section even though the facts are such that the commission of the further offence is impossible.
A person guilty of an offence under this section shall be liable—
on summary conviction in England and Wales, to imprisonment for a term not exceeding the general limit in a magistrates’ court or to a fine not exceeding the statutory maximum or to both;
on summary conviction in Scotland, to imprisonment for a term not exceeding 12 months or to a fine not exceeding the statutory maximum or to both;
on conviction on indictment, to imprisonment for a term not exceeding five years or to a fine or to both.
A person is guilty of an offence if—
he does any unauthorised act in relation to a computer;
at the time when he does the act he knows that it is unauthorised; and
either subsection (2) or subsection (3) below applies.
This subsection applies if the person intends by doing the act—
to impair the operation of any computer;
to prevent or hinder access to any program or data held in any computer; or
to impair the operation of any such program or the reliability of any such data; or
to enable any of the things mentioned in paragraphs (a) to (c) above to be done.
This subsection applies if the person is reckless as to whether the act will do any of the things mentioned in paragraphs (a) to (d)to (c) of subsection (2) above.
any particular computer;
any particular program or data or a program or data of any particular kind; or
any particular modification or a modification of any particular kind.
The intention referred to in subsection (2) above, or the recklessness referred to in subsection (3) above, need not relate to—
any particular computer;
any particular program or data; or
a program or data of any particular kind.
In this section—
a reference to doing an act includes a reference to causing an act to be done;
“act” includes a series of acts;
a reference to impairing, preventing or hindering something includes a reference to doing so temporarily.
A person guilty of an offence under this section shall be liable—
on summary conviction in England and Wales, to imprisonment for a term not exceeding the general limit in a magistrates’ court or to a fine not exceeding the statutory maximum or to both;
on summary conviction in Scotland, to imprisonment for a term not exceeding 12 months or to a fine not exceeding the statutory maximum or to both;
on conviction on indictment, to imprisonment for a term not exceeding ten years or to a fine or to both.
A person guilty of an offence under this section shall be liable—
on summary conviction, to imprisonment for a term not exceeding six months or to a fine not exceeding the statutory maximum or to both; and
on conviction on indictment, to imprisonment for a term not exceeding five years or to a fine or to both.
A person is guilty of an offence if—
the person does any unauthorised act in relation to a computer;
at the time of doing the act the person knows that it is unauthorised;
the act causes, or creates a significant risk of, serious damage of a material kind; and
the person intends by doing the act to cause serious damage of a material kind or is reckless as to whether such damage is caused.
Damage is of a “material kind” for the purposes of this section if it is—
damage to human welfare in any place;
damage to the environment of any place;
damage to the economy of any country; or
damage to the national security of any country.
For the purposes of subsection (2)(a) an act causes damage to human welfare only if it causes—
loss to human life;
human illness or injury;
disruption of a supply of money, food, water, energy or fuel;
disruption of a system of communication;
disruption of facilities for transport; or
disruption of services relating to health.
It is immaterial for the purposes of subsection (2) whether or not an act causing damage—
does so directly;
is the only or main cause of the damage.
In this section—
a reference to doing an act includes a reference to causing an act to be done;
“act” includes a series of acts;
a reference to a country includes a reference to a territory, and to any place in, or part or region of, a country or territory.
A person guilty of an offence under this section is (unless subsection (7) applies) liable, on conviction on indictment, to imprisonment for a term not exceeding 14 years, or to a fine, or to both.
Where an offence under this section is committed as a result of an act causing or creating a significant risk of— a person guilty of the offence is liable, on conviction on indictment, to imprisonment for life, or to a fine, or to both.
serious damage to human welfare of the kind mentioned in subsection (3)(a) or (3)(b), or
serious damage to national security,
A person is guilty of an offence if he makes, adapts, supplies or offers to supply any article intending it to be used to commit, or to assist in the commission of, an offence under section 1, 3 or 3ZA.
A person is guilty of an offence if he supplies or offers to supply any article believing that it is likely to be used to commit, or to assist in the commission of, an offence under section 1, 3 or 3ZA.
A person is guilty of an offence if he obtains any article— its being supplied for use to commit, or to assist in the commission of, an offence under section 1, 3 or 3ZA.
intending to use it to commit, or to assist in the commission of, an offence under section 1, 3 or 3ZA, or
with a view to
In this section “ article ” includes any program or data held in electronic form.
A person guilty of an offence under this section shall be liable—
on summary conviction in England and Wales, to imprisonment for a term not exceeding the general limit in a magistrates’ court or to a fine not exceeding the statutory maximum or to both;
on summary conviction in Scotland, to imprisonment for a term not exceeding 12 months or to a fine not exceeding the statutory maximum or to both;
on conviction on indictment, to imprisonment for a term not exceeding two years or to a fine or to both.
Except as provided below in this section, it is immaterial for the purposes of any offence under section 1, 3 or 3ZA above—
whether any act or other event proof of which is required for conviction of the offence occurred in the home country concerned; or
whether the accused was in the home country concerned at the time of any such act or event.
Subject to subsection (3) below, in the case of such an offence at least one significant link with domestic jurisdiction must exist in the circumstances of the case for the offence to be committed.
There is no need for any such link to exist for the commission of an offence under section 1 above to be established in proof of an allegation to that effect in proceedings for an offence under section 2 above.
Subject to section 8 below, where— section 2 above shall apply as if anything the accused intended to do or facilitate in any place outside the home country concerned which would be an offence to which section 2 applies if it took place in the home country concerned were the offence in question.
any such link does in fact exist in the case of an offence under section 1 above; and
commission of that offence is alleged in proceedings for an offence under section 2 above;
This section is without prejudice to any jurisdiction exercisable by a court in Scotland apart from this section.
It is immaterial for the purposes of an offence under section 3A whether the accused was in the home country concerned at the time of any act or other event proof of which is required for conviction of the offence if there is a significant link with domestic jurisdiction in relation to the offence.
References in this Act to the home country concerned are references—
in the application of this Act to England and Wales, to England and Wales;
in the application of this Act to Scotland, to Scotland; and
in the application of this Act to Northern Ireland, to Northern Ireland.
The following provisions of this section apply for the interpretation of section 4 above.
In relation to an offence under section 1, either of the following is a significant link with domestic jurisdiction—
that the accused was in the home country concerned at the time when he did the act which caused the computer to perform the function; or
that any computer containing any program or data to which the accused secured or intended to secure unauthorised access by doing that act was in the home country concerned at that time.
that any computer containing any program or data to which the accused secured or intended to secure unauthorised access by doing that act was in the home country concerned at that time.
that any computer containing any program or data to which the accused by doing that act secured or intended to secure unauthorised access, or enabled or intended to enable unauthorised access to be secured, was in the home country concerned at that time.
In relation to an offence under section 1, 3, 3ZA or 3A, where the accused was in a country outside the United Kingdom at the time of the act constituting the offence there is a significant link with domestic jurisdiction if—
the accused was a United Kingdom national at that time; and
the act constituted an offence under the law of the country in which it occurred.
In relation to an offence under section 3, either of the following is a significant link with domestic jurisdiction—
that the accused was in the home country concerned at the time when he did the unauthorised act (or caused it to be done) ; or
that the unauthorised act was done in relation to a computer in the home country concerned.
In subsection (1A)—
“country” includes territory;
“United Kingdom national” means an individual who is—
a British citizen, a British overseas territories citizen, a British National (Overseas) or a British Overseas citizen;
a person who under the British Nationality Act 1981 is a British subject; or
a British protected person within the meaning of that Act.
In relation to an offence under section 3ZA, any of the following is also a significant link with domestic jurisdiction—
that the accused was in the home country concerned at the time when he did the unauthorised act (or caused it to be done);
that the unauthorised act was done in relation to a computer in the home country concerned;
that the unauthorised act caused, or created a significant risk of, serious damage of a material kind (within the meaning of that section) in the home country concerned.
On a charge of conspiracy to commit an offence under this Act the following questions are immaterial to the accused’s guilt—
the question where any person became a party to the conspiracy; and
the question whether any act, omission or other event occurred in the home country concerned.
On a charge of attempting to commit an offence under this Act the following questions are immaterial to the accused’s guilt—
the question where the attempt was made; and
the question whether it had an effect in the home country concerned.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
This section does not extend to Scotland.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The following subsections shall be inserted after section 1(1) of the Criminal Attempts Act 1981—.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
what he had in view shall be treated as an offence under this Act for the purposes of any charge of incitement brought in respect of that act; and
any such charge shall accordingly be triable in England and Wales.
A person is guilty of an offence triable by virtue of section 4(4) above only if what he intended to do or facilitate would involve the commission of an offence under the law in force where the whole or any part of it was intended to take place.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
an act or omission by one or more of the parties; or
the happening of some other event;
A person is guilty of an offence triable by virtue of section 1(1A) of the Criminal Attempts Act 1981 . . . only if what he had in view would involve the commission of an offence under the law in force where the whole or any part of it was intended to take place.
Conduct punishable under the law in force in any place is an offence under that law for the purposes of this section, however it is described in that law.
Subject to subsection (7) below, a condition specified in subsection (1) or (3) above shall be taken to be satisfied unless not later than rules of court may provide the defence serve on the prosecution a notice—
stating that, on the facts as alleged with respect to the relevant conduct, the condition is not in their opinion satisfied;
showing their grounds for that opinion; and
requiring the prosecution to show that it is satisfied.
In subsection (5) above “the relevant conduct” means—
where the condition in subsection (1) above is in question, what the accused intended to do or facilitate;
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
where the condition in subsection (3) above is in question, what the accused had in view.
The court, if it thinks fit, may permit the defence to require the prosecution to show that the condition is satisfied without the prior service of a notice under subsection (5) above.
If by virtue of subsection (7) above a court of solemn jurisdiction in Scotland permits the defence to require the prosecution to show that the condition is satisfied, it shall be competent for the prosecution for that purpose to examine any witness or to put in evidence any production not included in the lists lodged by it.
In the Crown Court the question whether the condition is satisfied shall be decided by the judge alone.
In the High Court of Justiciary and in the sheriff court the question whether the condition is satisfied shall be decided by the judge or, as the case may be, the sheriff alone.
Except as provided by section 5(1A),In any proceedings brought in England and Wales in respect of any offence to which this section applies it is immaterial to guilt whether or not the accused was a British citizen at the time of any act, omission or other event proof of which is required for conviction of the offence.
This section applies to the following offences—
any offence under this Act ;
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
any attempt to commit an offence under this Act; and
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Sections 1 to 3A have effect without prejudice to the operation— in England and Wales of any enactment relating to powers of inspection, search or seizureor of any other enactment by virtue of which the conduct in question is authorised or required; and in Scotland of any enactment or rule of law relating to powers of examination, search or seizureor of any other enactment or rule of law by virtue of which the conduct in question is authorised or required and nothing designed to indicate a withholding of consent to access to any program or data from persons as enforcement officers shall have effect to make access unauthorised for the purposes of any of those sections. In this section— “ enactment ” means any enactment, whenever passed or made, contained in— an Act of Parliament; an Act of the Scottish Parliament; a Measure or Act of the National Assembly for Wales; an instrument made under any such Act or Measure; any other subordinate legislation (within the meaning of the Interpretation Act 1978); “ enforcement officer ” means a constable or other person charged with the duty of investigating offences; and withholding consent from a person “as” an enforcement officer of any description includes the operation, by the person entitled to control access, of rules whereby enforcement officers of that description are, as such, disqualified from membership of a class of persons who are authorised to have access.
in England and Wales of any enactment relating to powers of inspection, search or seizure; and
in Scotland of any enactment or rule of law relating to powers of examination, search or seizure.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
A magistrates' court shall have jurisdiction to try an offence under section 1 above if—
the accused was within its commission area at the time when he did the act which caused the computer to perform the function; or
any computer containing any program or data to which the accused secured or intended to secure unauthorised access by doing that act was in its commission area at that time.
Subject to subsection (3) below, proceedings for an offence under section 1 above may be brought within a period of six months from the date on which evidence sufficient in the opinion of the prosecutor to warrant the proceedings came to his knowledge.
No such proceedings shall be brought by virtue of this section more than three years after the commission of the offence.
For the purposes of this section, a certificate signed by or on behalf of the prosecutor and stating the date on which evidence sufficient in his opinion to warrant the proceedings came to his knowledge shall be conclusive evidence of that fact.
A certificate stating that matter and purporting to be so signed shall be deemed to be so signed unless the contrary is proved.
In this section “commission area” has the same meaning as in the Justices of the Peace Act 1979.
This section does not extend to Scotland.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
If on the trial on indictment of a person charged with— the jury find him not guilty of the offence charged, they may find him guilty of an offence under section 1 above if on the facts shown he could have been found guilty of that offence in proceedings for that offence brought before the expiry of any time limit under section 11 above applicable to such proceedings.
an offence under section 2 above; or
an offence under section 3 above or any attempt to commit such an offence;
The Crown Court shall have the same powers and duties in relation to a person who is by virtue of this section convicted before it of an offence under section 1 above as a magistrates' court would have on convicting him of the offence.
This section is without prejudice to section 6(3) of the Criminal Law Act 1967 (conviction of alternative indictable offence on trial on indictment).
This section does not extend to Scotland.
A sheriff shall have jurisdiction in respect of an offence under section 1 or 2 above if—
the accused was in the sheriffdom at the time when he did the act which caused the computer to perform the function; or
any computer containing any program or data to which the accused by doing that act secured or intended to secure unauthorised access, or enabled or intended to enable unauthorised access to be secured, was in the sheriffdom at that time.
A sheriff shall have jurisdiction in respect of an offence under section 3 above if—
the accused was in the sheriffdom at the time when he did the unauthorised act (or caused it to be done) ; or
the unauthorised act was done in relation to a computer in the sheriffdom.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
A sheriff shall have jurisdiction in respect of an offence under section 3ZA above if—
the accused was in the sheriffdom at the time when he did the unauthorised act (or caused it to be done), or
the computer in relation to which the unauthorised act was done was in the sheriffdom at that time.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
A sheriff shall have jurisdiction in respect of an offence under section 3A above if—
the accused was in the sheriffdom at the time when—
he made, adapted, supplied or offered to supply the article intending it to be used as mentioned in subsection (1) of that section,
he supplied or offered to supply the article believing that it would be used as mentioned in subsection (2) of that section, or
he obtained the article intending to use it, or with a view to its being supplied for use, as mentioned in subsection (3) of that section; or
the offence related to the commission of an offence under section 1, 3 or 3ZA above (in the way described in subsections (1) to (3) of section 3A above) and any computer as mentioned in subsection (1)(b), (2)(b) or (2A)(b) of this section was in the sheriffdom at the time the accused carried out the act constituting the offence under section 3A above.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
In proceedings in which a person is charged with an offence under section 2 or 3 above and is found not guilty or is acquitted of that charge, he may be found guilty of an offence under section 1 above if on the facts shown he could have been found guilty of that offence in proceedings for that offence . . . .
Subsection (8) above shall apply whether or not an offence under section 1 above has been libelled in the complaint or indictment.
A person found guilty of an offence under section 1 above by virtue of subsection (8) above shall be liable, in respect of that offence, only to the penalties set out in section 1.
This section extends to Scotland only.
Where an offence under section 1, 3, 3ZA or 3A above is committed outside Scotland, the person committing the offence may be prosecuted, tried and punished for the offence— as if the offence had been committed in that district; and the offence is, for all purposes incidental to or consequential on the trial or punishment, deemed to have been committed in that district.
in any sheriff court district in Scotland in which the person is apprehended or is in custody, or
in such sheriff court district as the Lord Advocate may direct,
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Where a circuit judge is satisfied by information on oath given by a constable that there are reasonable grounds for believing— he may issue a warrant authorising a constable to enter and search the premises, using such reasonable force as is necessary.
that an offence under section 1 above has been or is about to be committed in any premises; and
that evidence that such an offence has been or is about to be committed is in those premises;
The power conferred by subsection (1) above does not extend to authorising a search for material of the kinds mentioned in section 9(2) of the Police and Criminal Evidence Act 1984 (privileged, excluded and special procedure material).
A warrant under this section—
may authorise persons to accompany any constable executing the warrant; and
remains in force for twenty-eight days from the date of its issue.
In executing a warrant issued under this section a constable may seize an article if he reasonably believes that it is evidence that an offence under section 1 above has been or is about to be committed.
In this section “premises” includes land, buildings, movable structures, vehicles, vessels, aircraft and hovercraft.
This section does not extend to Scotland.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
offences under section 2 or 3 above;
any conspiracy to commit such an offence; and
any attempt to commit an offence under section 3 above.
The following provisions of this section have effect for applying this Act in relation to Northern Ireland with the modifications there mentioned.
In section 2(2)(b)—
the reference to England and Wales shall be read as a reference to Northern Ireland; and
the reference to section 33 of the Magistrates’ Courts Act 1980 shall be read as a reference to Article 46(4) of the Magistrates’ Courts (Northern Ireland) Order 1981.
In section 1(3)(a)—
the reference to England and Wales shall be read as a reference to Northern Ireland; and
the reference to the general limit in a magistrates’ court shall be read as a reference to six months.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Subsection (7) below shall apply in substitution for subsection (3) of section 7; . . . .
In section 2(5)(a)—
the reference to England and Wales shall be read as a reference to Northern Ireland; and
the reference to the general limit in a magistrates’ court shall be read as a reference to six months.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
In section 3(6)(a)—
the reference to England and Wales shall be read as a reference to Northern Ireland; and
the reference to the general limit in a magistrates’ court shall be read as a reference to six months.
The following paragraphs shall be inserted after Article 3(1) of that Order—.
In section 3A(5)(a)—
the reference to England and Wales shall be read as a reference to Northern Ireland; and
the reference to the general limit in a magistrates’ court shall be read as a reference to six months.
In section 8—
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
the reference in subsection (3) to section 1(1A) of the Criminal Attempts Act 1981 shall be read as a reference to Article 3(1A) of that Order.
The references in sections 9(1) and 10 to England and Wales shall be read as references to Northern Ireland.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
the reference in subsection (1) to a circuit judge shall be read as a reference to a county court judge; and
the reference in subsection (2) to section 9(2) of the Police and Criminal Evidence Act 1984 shall be read as a reference to Article 11(2) of the Police and Criminal Evidence (Northern Ireland) Order 1989.
In section 10 the definition of “enactment” shall be read as including a reference to an enactment, whenever passed or made, contained in Northern Ireland legislation or in an instrument made under such legislation.
The following provisions of this section apply for the interpretation of this Act.
A person secures access to any program or data held in a computer if by causing a computer to perform any function he— and references to access to a program or data (and to an intent to secure such access or to enable such access to be secured) shall be read accordingly.
alters or erases the program or data;
copies or moves it to any storage medium other than that in which it is held or to a different location in the storage medium in which it is held;
uses it; or
has it output from the computer in which it is held (whether by having it displayed or in any other manner);
For the purposes of subsection (2)(c) above a person uses a program if the function he causes the computer to perform—
causes the program to be executed; or
is itself a function of the program.
For the purposes of subsection (2)(d) above—
a program is output if the instructions of which it consists are output; and
the form in which any such instructions or any other data is output (and in particular whether or not it represents a form in which, in the case of instructions, they are capable of being executed or, in the case of data, it is capable of being processed by a computer) is immaterial.
Access of any kind by any person to any program or data held in a computer is unauthorised if—
he is not himself entitled to control access of the kind in question to the program or data; and
he does not have consent to access by him of the kind in question to the program or data from any person who is so entitled but this subsection is subject to section 10.
References to any program or data held in a computer include references to any program or data held in any removable storage medium which is for the time being in the computer; and a computer is to be regarded as containing any program or data held in any such medium.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
any program or data held in the computer concerned is altered or erased; or
any program or data is added to its contents;
An act done in relation to a computer is unauthorised if the person doing the act (or causing it to be done)— In this subsection “ act ” includes a series of acts.
is not himself a person who has responsibility for the computer and is entitled to determine whether the act may be done; and
does not have consent to the act from any such person.
References to the home country concerned shall be read in accordance with section 4(6) above.
References to a program include references to part of a program.
Where a county court judge is satisfied by information on oath given by a constable that there are reasonable grounds for believing— he may issue a warrant authorising a constable to enter and search the premises, using such reasonable force as is necessary.
that an offence under section 1 above has been or is about to be committed in any premises, and
that evidence that such an offence has been or is about to be committed is in those premises,
The power conferred by subsection (1) above does not extend to authorising a search for material of the kinds mentioned in Article 11(2) of the Police and Criminal Evidence (Northern Ireland) Order 1989 (privileged, excluded and special procedure material).
A warrant under this section—
may authorise persons to accompany any constable executing the warrant; and
remains in force for twenty-eight days from the date of its issue.
In exercising a warrant issued under this section a constable may seize an article if he reasonably believes that it is evidence that an offence under section 1 above has been or is about to be committed.
In this section “ premises ” includes land, buildings, movable structures, vehicles, vessels, aircraft and hovercraft.
This section extends only to Northern Ireland.
This Act may be cited as the Computer Misuse Act 1990.
This Act shall come into force at the end of the period of two months beginning with the day on which it is passed.
An offence is not committed under this Act unless every act or other event proof of which is required for conviction of the offence takes place after this Act comes into force.