Peter Lilley: MPs who took drugs have 'disabled' their brains The only reason that I have a clear head on cannabis is that I've never taken any. Much of my friends, colleagues in this place did and don't seem to have recovered. The home affair select committee recommended a Royal Commission The report comes 10 years after the committee's last inquiry into drugs, when David Cameron was among its members, also called for the government to look at the legalisation of some banned substances. A biography of Mr Cameron has claimed that he was caught smoking cannabis while at Eton, aged 15. Mr Cameron has insisted that MPs are entitled to keep their lives before they entered politics private. A number of high profile politicians have confessed to experimenting with cannabis as students in recent years. Jacqui Smith admitted shortly after becoming Home Secretary under Gordon Brown in 2007 that she had taken cannabis while a student at Oxford. "I am not proud about it, I did the wrong thing," she said at the time. Last November she said she had been wrong as a minister to introduce stricter controls on cannabis after ignoring the evidence from a panel of experts. Last year, Chuka Umunna, the current shadow business secretary, also confessed to smoking marijuana when he was a teenager. He insisted he had not taken any harder drugs. In the interview, Mr Lilley described the Energy Minister, Greg Barker, as "barking mad," and warned that the government should not have claimed to be "the greenest ever." He also suggested that he would be happy to return to the front bench, but questioned whether it would be the most sensible decision for the Prime Minister to make. "You can bring experience into a particular department, but it's not like the flu, you can't infect the rest of the Cabinet with experience," he said. I can't really convince myself that it would necessarily be the best decision for Cameron to bring back people like me.