Conspiracy offences explained

Oct 31, 2025 | By: Vicky Lankester

Conspiracy is an offence by virtue of section 1(1) Criminal Law Act 1977. This sets out that a person is guilty of a conspiracy if:

They agree with someone else or multiple people to carry out a course of conduct, and
If the agreement is carried out as intended, either:
It will amount to or involve the commission of any offence(s) by one or more parties to the agreement; or
Would amount to or involve the commission of any offence(s) but for the existence of facts which render the commission of the offence(s) impossible.

There also has to be knowledge and/or intention on that person’s part to be a party to an agreement to commit a crime in order to be guilty of the conspiracy. This can often be difficult for prosecutors to prove, as people rarely leave hard evidence of them being involved in an agreement to commit an offence.

Conspiracy is an offence that can only be tried in the Crown Court. Someone found guilty of a conspiracy offence will be sentenced according to the Sentencing Guidelines for the substantive offence which they were conspiring to carry out, with an uplift to take account of the seriousness of the conspiracy element. Most of the time, someone found guilty of a conspiracy offence should expect to receive an immediate custodial sentence.

The interesting point about a conspiracy is that no substantive criminal offence actually has to be carried out for someone to be guilty of an offence. It is known as an “inchoate” offence, meaning an offence is committed simply when taking a step towards committing a crime. The essential element of a conspiracy is an agreement by two or more people to carry out a criminal act. Even if nothing is done in furtherance of the agreement, i.e. even if the agreement goes no further, the offence of conspiracy can still be made out. Other inchoate offences include attempts (when someone tries to commit an offence but fails) and solicitation (when someone offers someone else money to commit an offence). In contrast to those offences, however, is that a person can be charged with both a conspiracy and the substantive offence (e.g. conspiracy to commit criminal damage and criminal damage). It is not possible to charge a person with both an attempt or solicitation and the substantive offence.