"Three Labour MPs are said to be terrified that the release of their expenses claims will expose them as adulterers and financial cheats.
Four ministers are also understood to have warned party whips they might have to resign for abusing the system, when MPs' receipts are published before the summer recess in July.
The three unnamed backbenchers are said to have been placed on 'suicide watch' by Labour whips, who fear they might break down when the details of their excesses come out.
Two are understood to have had extra-marital affairs with other members of Parliament.
Not only are they believed to have shared hotel rooms during annual conference get-togethers and party away days but also to have double-claimed for the rooms on their expenses.
If both MPs have claimed for the bill they will be branded frauds as well as love cheats when journalists and freedom of information campaigners sift through their receipts.
The third backbencher is said to have made 'grotesque' financial claims.