PRIME Minister's Question Time today should be rather more interesting than usual. The big issue will presumably be the allegations that the Labour MP Sadiq Khan was “bugged” when he talked with a prisoner, a constituent of his, at Woodhill Prison in 2005 and 2006. There seems no doubt that recordings were made, which is an issue in itself, but the Conservatives are trying to use the case to demonstrate once again that ministers are not in charge of their departments; it seems that Home Office and Ministry of Justice officials knew about the recordings but decided not to tell their ministers, Jacqui Smith and Jack Straw respectively. Yesterday David Davis raised the political temperature by accusing the Prime Minister of being “a liar, basically” because the bugging of an MP breaks Gordon Brown's undertaking to the Commons that he would follow the 40-year-old Wilson Doctrine which prohibits the covert recording of MP's conversations with their constituents. This is a serious matter with many implications, not only for MPs. The government has set up an inquiry which will report in two weeks. Mr Davis's “liar” accusation against Gordon Brown was over the top and either he or Mr Cameron should withdraw it. Today Mr Cameron would be well advised to pursue the matter responsibly and calmly; it should not be handled in the “Punch and Judy” style which the Conservative leader once said he disliked but now seems to use almost every week.