Boris Johnson was embroiled in an astonishing row last night after he attacked the TV chef Jamie Oliver and his campaign for healthier school dinners. The shadow higher education minister criticised Oliver's crusade days after David Cameron endorsed the chef's campaign. Mr Johnson even offered support to the mothers in Yorkshire who passed fast food to their children through the school fence in protest at the introduction of "over-priced, low-fat rubbish" in the school canteen. "I say let people eat what they like. Why shouldn't they push pies through the railings?" Mr Johnson told a fringe meeting in Bournemouth. "I...