Bob Ainsworth MP, a former Home Office drugs minister, is to call for the decriminalisation of all drugs in a Westminster Hall debate.
Mr Ainsworth told Today presenter James Naughtie that he was "overwhelmingly concerned" with the most dangerous of drugs, particularly heroin.
"I'm not proposing the liberalisation and the legalisation of heroin so we can all get zonked out on the street corner," he said.
Heroin, he said, needed to be taken out of the hands of drug dealers and into the hands of the medical profession.
"This has been going on for 50 years now and it isn't getting better. The drugs trade is as big, as powerful as it ever was across the world," he said.
"Prohibition isn't the answer to this problem."
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