Cameron 'warned alcohol policy could be illegal by own ministers' In a letter broadcast on Channel 4 yesterday, MP David Willetts told the Prime Minister he considered the minimum unit pricing "very likely to be deemed illegal" under competition and trade law. The minister added the Attorney General had already written saying the policy "carries a significant degree of legal risk." The letter is understood to have been sent four days before Mr Cameron publicly outlined the proposal to tackle the "scourge of violence" on Britain's high streets. In March, it was reported that officials privately acknowledged the policy faced a number of difficulties and could be held up in legal challenges over whether it discriminates against some drink producers. The proposal, which would see a 40p minimum price per unit of alcohol, would mean a four-pack of lager cannot be sold for less an £3.32 and a bottle of wine will be at least £3.60. At the time, Mr Cameron said he believed the policy might not be popular but would save lives. A spokeswoman for the Department for Business Innovation and Skills said she could not comment on individual letters between ministers. She added: "The government is continuing to take legal advice on this and considering any potential legal implications as part of a forthcoming consultation."