This piece is not going to win much agreement, so first, let me make my basic position clear. I am not an admirer of MPs as a genus. They are ineffectual and supine, submitting too easily to their party line. They got where they are by the outrageously archaic and unrepresentative First Past the Post electoral system, and they are unwilling to change it. They are happy to let corporations take over domination of the world. They do not understand where money comes from. They are like sheep. They do not give straight answers. And so on and so forth. Get it? I am not a friend of MPs.
Having said that, it is a principle in law that new laws are not applied retrospectively. If the expenses system administered by the Civil Service previously was crap. We all deserve a better system. But applying a better system retrospectively is dubious, and I for one will not criticise an MP that challenges the ruling of "Sir" Thomas Legg.