I’m not going to comment on the Derek Conway matter, other than to say I would have thought he had more sense.
But I will say again, as I have before, that we must not generalize and let individual cases tar the whole system.
In fact, the House of Commons authorities have strict rules about Members’ staff, will only include them on the payroll if there is a proper contract of employment, and these days there are also scales of appropriate payment for particular jobs.
Most of the wives, sons and daughters, and a few husbands, who work for their spouse or parent are doing a fairly thankless job, working hard, and putting in long hours to do all in their power to make sure the MP is providing a good service to his/her constituents.
Part of the time that I worked in the Commons, I had the privilege to be located around the other side of the horseshoe that was the Lower Ministerial Corridor from the office of Neil Hamilton, where the doughty Christine presided. I can say with absolute certainty, not least because of the volume of her voice, that here was one MP’s wife who was in the office and working hard all day.
Sepoy Agent 
A few years ago I would have agreed with you, however it’s gone too far now. The abuse of expenses seen by many MP’s as perks is an unregulated mess. You try spending up to £250 of your employers money in the real world without producing a receipt and see what happens to you. Nepotism and this is what the whole mess stinks of is not a good way to conduct the business of governance. They (the relatives) may work damned hard, but appearances make it seem as if the money is being kept “in house”. Until the whole mess of expenses is sorted and some draconian penalties set in place for abuse then as far as the public as a whole is concerned politicians are just another bunch of greedy corrupt chancers.
I agree that many family members do a great job, but to say that Tony Conway should have had more sense is an understatement! He knowingly and deliberately screwed thousands of pounds out of the taxpayer.
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My comment that I thought Derek Conway had more sense was not a comment on what he had done. It was simply that, from what I know of him, I found it difficult to believe he would do such a thing.
I agree that what he has done is totally unacceptable, and has made great difficulty for those family members of other MPs who are doing a good job.