R v Nock [1978] 1 WLR 1598
Court: Court of Appeal (Criminal Division)
Facts: D agreed to produce cocaine from a substance they believed contained cocaine, which in fact contained none.
Held: Conviction quashed. The court ruled that there was no conspiracy to produce cocaine as the substance was not as believed, and the defence of impossibility applied.
Key Judicial Statement: Lord Justice Lawton remarked, "A conspiracy charge fails if the factual basis of the intended crime does not exist, rendering the agreement to commit a non-existent crime impossible."