I almost thought David Cameron had started to nail the issue of MPs expenses yesterday. He seemed, at any rate, to understand the need for the 'S' word. Then, this morning, on BBC Breakfast, his Defence Spokesman, Liam Fox - presumably being wheeled out because his expenses are ok - ruined it all, with a pathetic, rambling performance in which he was no better than the bleating Blears yesterday. The system is what's wrong. It must be changed. That was Fox's futile mantra. Has he really no ability to understand how deep this runs? He had a golden opportunity to develop Cameron's line, and show that he too was made of leadership fibre - and he fell flat on his face.