This is the problem nowdays. Politics is seen as a profession. Years ago people went into politics to serve and they usually had some sort of expertise in a particular field.
The modern day MP has never done a days work in their life with the exception of 1 or 2. We have had a series of Chancellors across both Parties who have had no real experience in the world of finance, yet we allow them to control the countries finances.
The expenses thing is a joke especially when alot of them hire family members who probably don't do a thing.
It's possible to become a millionaire now just by being a politician. Ask Neil KInnock.