Conspiracy to commit murder is a criminal offence under Section 1(1) of the Criminal Law Act 1977. It is committed the moment two or more people agree on a plan that would result in someone’s death even if the killing never actually happens.
Because murder itself carries a maximum sentence of life imprisonment, anyone convicted of conspiring to commit it faces the same maximum penalty. This guide covers the legal meaning, sentencing, and defences under England and Wales law.
Conspiracy to murder means agreeing with at least one other person to pursue a course of conduct that, if carried out as planned, would amount to murder. Like any conspiracy charge, it’s one of the law’s “inchoate” offences — meaning it punishes the planning of a crime, not just its completion. The offence is complete the instant the agreement is formed: no one needs to be hurt, no weapon needs to be bought, and no attempt needs to be made.
To secure a conviction, the Crown Prosecution Service (CPS) must prove that:
That last point matters more than it might seem. For the completed offence of murder, an intention to cause grievous bodily harm (GBH) is enough for a conviction. For conspiracy to murder, it isn’tthe prosecution must show a specific intent to kill, which is a higher bar and often the central issue at trial.
The agreement also has to be realistic, not just a passing comment vague talk that only “sort of” sounds like a plot, with no real plan behind it, won’t meet the legal test.
| Offence | What Must Be Proven | Maximum Sentence |
|---|---|---|
| Conspiracy to murder | Agreement between two or more people, with intent to kill. No act toward the killing is required. | Life imprisonment (discretionary) |
| Attempted murder | An act “more than merely preparatory” to killing, done with intent to kill. Victim survives. | Life imprisonment (discretionary) |
| Murder | The killing is completed, with intent to kill or cause grievous bodily harm. | Life imprisonment (mandatory) |
The maximum sentence for conspiracy to commit murder is life imprisonment, set out in Section 3(2) of the Criminal Law Act 1977 the same ceiling that applies to murder itself. Unlike murder, though, that life sentence isn’t automatic. For murder, life imprisonment is mandatory by law. For conspiracy, the judge has discretion over the length of sentence, up to and including life, based on how serious the plan was.
All cases are heard in the Crown Court, since conspiracy to murder is an indictable offence. Judges typically weigh:
In each case, guilt turns on the agreement and the intent behind it not on whether the killing actually took place.
Yes. Under Section 1A of the Criminal Law Act 1977, a conspiracy formed even partly in England and Wales to murder someone abroad can still be prosecuted here, provided the killing would also be a crime in the country where it was intended to happen. Since murder is a crime in every country, that condition is virtually always met.
Under Section 2 of the Criminal Law Act 1977, an agreement cannot be charged as a conspiracy if the only other person involved is:
These exemptions only apply where the co-conspirator is one of these people and no one else. Bring one more adult into the plan, and the exemption no longer applies.
Entering an agreement purely to expose or prevent a crime as an undercover officer might isn’t automatically a defence if the plan is allowed to progress too far before an arrest. A genuine suicide pact isn’t conspiracy to murder either, since the agreement is with the intended victim (see the exemption above) though killing the other party and surviving can still raise a partial defence to murder.
Being investigated or charged with conspiracy to commit murder is serious, and early, specialist legal advice can make a significant difference to how your case is handled. At Stuart Miller Solicitors, our criminal defence team has secured acquittals for thousands of defendants at the Crown Court. Contact us for a no obligation consultation.
Conspiracy is the agreement itself it’s complete once two or more people agree on a plan, regardless of what happens next. Attempted murder requires an actual step toward the killing, taken with intent to kill, where the victim survives.
Yes. The offence doesn’t require any harm or attempt the agreement and the intent behind it are what make it a crime.
Life imprisonment, under Section 3(2) of the Criminal Law Act 1977 the same maximum that applies to murder itself.
No. Unlike murder, where life imprisonment is compulsory, a court has discretion over sentence length for conspiracy, up to and including life, depending on culpability and harm.
Not if they’re the only other person involved in the agreement spouses and civil partners are exempt under Section 2 of the Criminal Law Act 1977. That exemption disappears the moment a third person joins the plan.
No. Conspiracy to murder requires specific intent to kill. Intent to cause grievous bodily harm enough for a murder conviction if a death results isn’t enough on its own for a conspiracy to murder charge.
Withdrawing doesn’t undo an agreement that’s already been made, since the offence is typically complete once the agreement exists. Genuine withdrawal before a firm agreement was reached may instead support a “negotiations only” defence.
Yes, under Section 1A of the Criminal Law Act 1977, provided the agreement was formed at least partly in England and Wales and the killing would also be illegal in the country where it was planned to take place.
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