Deputy Prime Minister Nick Clegg has called for sweeping changes to Britain's "idiotic" policy on drugs.

The Liberal Democrat leader said addiction should be treated as a health problem not a criminal issue.

In a question and answer session at the Lib Dem conference in Glasgow, he also accused the Conservative Party of blocking his party's attempts to reform the law.

The Lib Dems have long argued for changes to Britain's drug laws.

Mr Clegg said: "Treat the people with addictions in the way that they need to be dealt with, which is that they need help."

'Frightfully conservative'

It was wrong to jail people for personal possession of drugs, he said, because they often emerged as criminals or fall into the hands of criminal gangs.

"How idiotic is that? You are not actually dealing with the health problem, and you are making it easier for the criminals to derive profits off these addicts."

Mr Clegg said responsibility for drug addiction should be moved to the Department of Health, to allow the Home Office to "go after the 'Mr Bigs' who we should be much tougher on".

He said the Conservatives had "dragged their feet" on the issue, resisting Lib Dem calls for a Royal Commission to investigate and leaving a report "stuck in the bowels of Whitehall".

He added: "It is rather frustrating that in something where we could be leading the debate, the Conservatives in government are being so frightfully conservative."

Mr Clegg said he believed there was widespread support for changes, saying it was "one of those classic examples where the political class is behind the rest of the country".