Inchoate offences

Attempt is governed by section 1 of the Criminal Attempts Act 1981: a person is guilty if, with intent to commit an offence, they do an act that is 'more than merely preparatory' to its commission. Whether conduct crosses that line is a question for the jury — in R v Geddes a man found in school toilets with a knife and rope had not gone beyond preparation, whereas a defendant who has embarked on the offence proper will have.

Conspiracy is an agreement between two or more people to pursue a course of conduct that will necessarily amount to an offence (statutory conspiracy under section 1 of the Criminal Law Act 1977). Encouraging or assisting an offence replaced the old common law offence of incitement and now sits in sections 44 to 46 of the Serious Crime Act 2007.

The mens rea is demanding: attempt requires an intention to commit the full offence, even where the substantive crime can itself be committed recklessly. Impossibility is generally no defence — in R v Shivpuri the House of Lords held that a defendant who dealt in what he believed were prohibited drugs was guilty of attempt even though the substance turned out to be harmless.