(Just realised that looks like a Daily Mail headline..!)
All this stuff has just blown up about David Laws, the Liberal Treasury Secretary Claiming expenses for renting a room from his partner.....
Well MPs are allowed to claim on a second home in London. Theoretically his partner could have rented out his own flat and lived rent free in a flat rented by David Laws. DL would then reclaimed that rent as expenses and he would have been within the rules, and it would probably in total have cost the taxpayer more money.
Also given the inevitable headlines about having a "gay lover", David Laws understandadbly wanted to keep his sexuality private