The UK Defence Secretary Liam Fox has resigned after a week of pressure over his working relationship with friend and self-styled adviser Adam Werritty. He has been under investigation amid claims that he broke the ministerial code of conduct. In a letter to David Cameron, Mr Fox said he had "mistakenly allowed" personal and professional responsibilities to be "blurred". Mr Cameron said he was very sorry for Mr Fox's departure. Transport Secretary Philip Hammond will replace Mr Fox with immediate effect.