"wholly, exclusively and necessarily"

Whilst you peruse the heavily censored MPs expenses now available on the web, do bear in mind that every claim has to be signed by the MP next to the declaration that the costs were

"incurred wholly, exclusively and necessarily in the performance of my Parliamentary duties"

Remember that declaration every time you see a receipt for cutting logs or even £700 for a year's newspapers (more on that one later..), "wholly, exclusively and necessarily in the performance of my Parliamentary duties"
Why should any claims for items other than those that meet that tight requirement be seen as anything other than fraudulent?