Dame Judi Dench, Sting and Julie Christie have urged Prime Minister David Cameron to decriminalise possession of all drugs. In an open letter to him they call for "a swift and transparent review of the effectiveness of drug policies".
The letter, which was published by the campaign group Release, says: "It is clear that the present system of applying the criminal law to the personal use and possession of drugs has failed."
It says nearly 80,000 people in the UK were convicted or cautioned for possessing drugs last year and "most were young, black or poor".
The letter from the celebrities comes as the Global Commission on Drug Policy, whose members include tycoon Sir Richard Branson, admits that the war on drugs has failed. He said that a new approach "that takes the power out of the hands of organised crime" was needed.