Perverting the course of justice

What is perverting the course of justice?

Perverting the course of justice is an English common law crime. It involves someone preventing justice from being served on themselves or on someone else. A serious criminal offence, perverting the course of justice is triable on indictment only. Other crimes, such as perjury, fraud or witness tampering can also amount to perverting the course of justice, but would be charged under the relevant statutory law.

To pervert the course of course of justice, any one of the three acts below must be carried out:

  1. Intimidating or interfering with a case witness, juror or judge;
  2. The disposal, or fabricating, of evidence;
  3. Falsely accusing someone of a crime, resulting in their arrest.

For a charge of perverting the course of justice to stick, it must involve conslusive acts by the defendant. However, a simple omission is insufficient.

What constitutes threatening or interfering with a witness?

Intimidation is defined as:

Making threats to physically or financially harm someone or acts/threats against a third party (eg, a relative of a case witness), with the purpose of deterring the witness from giving evidence in court.

What constitutes disposing of or fabricating evidence?

Any evidence which is linked to a case must not be tampered with or damaged in any way. Disposing of evidence means completely getting rid of something which is vital to solving the case (eg, throwing it away). Fabricating evidence involves altering or falsifying evidence in the hope of misleading the court.


Perjury is another way of perverting the course of justice. Under s 1(1) of the Perjury Act 1911, this is when ‘a lawfully sworn witness or interpreter in judicial proceedings wilfully makes a false statement which he knows to be false or does not believe to be true, and which is material in the proceedings’. The act of perjury is therefore to give a false statement which you know is not true.

Perjury is only triable on indictment and carries a maximum penalty of seven years imprisonment and/or a fine.

A conviction for perjury cannot be solely based on the evidence of one witness as to the falsity of any statement. There must be some other evidence – eg, a letter written by the defendant contradicting their own evidence. This is sufficient if supported by a single witness. A witness who tells the court something which s/he believes to be untrue – even if it later emerges to be true after all – is still guilty of perjury.

Lying at the police station

The course of justice can also be perverted where a solicitor or legal representative knowingly assists a client in deceiving the police.

If a client makes an admission to a legal adviser, they must advise the client that if they wish to wrongfully mislead the police by making a written or oral statement they can no longer represent them. If the client gives any answers in the interview which the legal adviser knows to be untrue, s/he must stop the interview and advise the client.

If the legal adviser decides they can no longer act for the client, s/he must withdraw in a way that does not indicate to the police the reason for withdrawing.

Each of the following matters must be proven beyond a reasonable doubt for the police to prove their case at court:

  • The accused did any act, or made any admission.
  • The accused intended to pervert the course of justice.


The maximum sentence that can be imposed for perverting the course of justice is life imprisonment and/or a fine. However, Crown Prosecution Service (CPS) sentencing guidelines recommend a prison sentence for this crime of between four and 36 months.


There are possible defences to perverting the course of justice including:

  • Genuine mistake or error
  • Duress
  • Necessity

Notable cases

Some of the most high-profile convictions in recent history for perverting the course of justice include:

Article written by...
Lucy Trevelyan LLB
Lucy Trevelyan LLB

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Lucy graduated in law from the University of Greenwich, and is also an NCTJ trained journalist. A legal writer and editor with over 20 years' experience writing about the law.