A serving MP has reported six of his parliamentary colleagues - including two former Cabinet ministers - to police over alleged abuse of expenses, it has been reported.
The Sunday Times claimed that the Labour MP, who represents a northern constituency, passed details of alleged wrongdoing to police because he believes he was unfairly singled out for investigation over his own allowances.
If confirmed, it would be the first time since the expenses scandal erupted in 2009 that an MP has made a complaint to police about fellow members of the Commons.
According to the paper, the politicians against whom the complaints have been made include two Labour MPs, two Conservatives and two Liberal Democrats.
Scotland Yard said that "a small number" of parliamentary expenses cases remain under consideration by a panel of detectives and prosecutors, but was unable to say whether any fresh cases had been brought to their attention recently.
A spokesman said the Met does not reveal the identity of its informants in such cases.
Some 10 files have been handed to the Crown Prosecution Service by the Met's economic and specialist crime unit, of which six led to charges and two to no further action being taken, while two others remain under consideration.
Former Labour MP David Chaytor was jailed for 18 months earlier in January after admitting false accounting, while Barnsley Central MP Eric Illsley has announced he will step down from Parliament after entering a guilty plea to dishonestly claiming more than £14,000. He will be sentenced next month.
According to the Sunday Times, the MP who passed on his colleagues' names has been the subject of a police investigation, but is not one of the four politicians awaiting trial. He has reportedly highlighted claims by colleagues which were similar to his own expenses for household expenditure like council tax, maintenance and utility bills.
The report comes ahead of the opening on Monday of the trial of Lord Taylor of Warwick, a former Conservative peer, who faces six charges of false accounting relating to 2006 and 2007. He pleaded not guilty at an earlier hearing.