Why are only junior MPs standing down?

There are already 11 MPs who have said they will step down at the next election as a direct result of the expenses scandal. How many more there will be is anyones guess. I have heard estimates of 200 or more potentially. The next House of Commons could have the highest new intake of any in history at this rate.

David Hughes has raised an interesting point though on the Telegraph Three Line Whip blog. He is asking what about the big fish and he has a very good point. None of the MPs who have announced they are stepping down were in Ministerial or Shadow Ministerial positions. Andrew MacKay was an adviser to Cameron but most of the public would not have heard of him.

What about Hazel Blears or Alistair Darling, Jacqui Smith, Geoff Hoon, Tony McNulty, Andrew Lansley, Oliver Letwin or Alan Duncan. These people have all been accused of what seems to me quite dodgy behavour around expenses but it is looking like there may be no consequences for them beyond having to pay the money back.

I suspect the reason is that there is a sort of compact (probably unspoken) between Brown and Cameron that neither will push this for fear of opening the floodgates and seeming to lose control and potentially many Ministers and Shadow Ministers for if an MP is forced to stand down at the next election they can surely no longer serve on the front bench.

I think as there are more and more MPs forced to stand down the public will start to ask why the political minnows are the ones sufferring and the large fry seem to be getting away with it. This is surely going to be unsustainable.