Boris Johnson reserved — and then exercised — the “right to make gaffes” yesterday as he suggested that the police were wasting their time by chasing cannabis smokers.

The Henley MP put himself at odds with the Tories’ zero-tolerance stance on drugs when he was asked whether he supported diverting police away from tackling cannabis possession.

The front-runner in the race to become the Conservative candidate for the London mayoralty made clear that he did not favour decriminalisation, but said that he wanted the police to focus on more serious crimes.

“I don’t want the police wasting their time rifling through the sock drawers of every student in London in the hope of finding a little rabbit dropping of cannabis. You know, I just think it’s a waste of their time,” he said during a television interview.

The official Tory position on cannabis is that it should be restored to the Class B drug category and that users should be routinely prosecuted.

Mr Johnson’s rivals lost little time in seeking to exploit his deviation. Victoria Borwick, who is campaigning on a pledge to introduce zero-tolerance policing to London, said: “I want the law enforced, without fear or favour.”

Although Mr Johnson’s remarks on cannabis will be unwelcome in the office of David Cameron — who narrowly avoided being expelled from Eton for smoking the drug — it is unlikely that they will do his bid serious damage. In the same interview Mr Johnson said: “I reserve the right to make gaffes, I really do. I think it is a key thing in politics that people should be able to say what they think and to get themselves into slight trouble from time to time.”

Mr Cameron, meanwhile, sought to distance himself from a recommendation that free car parking be scrapped at out-of-town superstores. “I fully understand the pressures that families feel in getting the weekly shop done and don’t want to make that more difficult,” the Tory leader said in the face of a hostile reaction to the proposal put forward by the Quality of Life policy group that reports tomorrow.

The group is also proposing a “pay-as-you-throw” policy for household waste-charging which punishes those who fail to recycle. Council tax bills should break down the cost of rubbish collection and include rebates for those that meet recycling targets, the group, chaired by John Gummer and Zac Goldsmith, will suggest.

“Household waste collection has to be paid for. If consumer behaviour is to be changed, there has to be a transparent linkage between waste disposal and its cost,” the report states.

Times Recommends

• Should Knox’s trial even have reached the courtroom?
• All that glitters is not sold in Wright’s world
• Believe it or not, Big Brother is your friend