Derek Conway has said he will stand down at the next election
The MP who had the Tory whip withdrawn after being criticised for paying his sons too much at public expense has questioned the way he was treated.
Derek Conway, whose case prompted the continuing row over MPs' expenses, stood up during a debate on the latest proposed reforms.
He said he believed 250 MPs employed close family, lovers or in-laws.
He also said guidance on pay rates was not clear and said he still bore "the scars" of the scrutiny he faced.
Mr Conway was expelled from the Conservative Party last year after being reprimanded by the Commons' Standards and Privileges Committee for overpaying his sons.
He was ordered to return £13,161 of public money paid to his younger son Freddie to work as a researcher while he was a student in Newcastle and later was ordered to return £3,757 of taxpayers' money paid to his elder son Henry.
In a surprise intervention in Thursday's debate Mr Conway contrasted the investigation into his family with that of an inquiry into Tory frontbencher Caroline Spelman's employment of a nanny.
In his case he said a secretary who had long since left his service had been tracked down and his son interviewed for two and a half hours, while in Ms Spelman's inquiry witnesses named in the press had not been spoken to.
"One does wonder if sometimes committees of this house ... does tend to bend over backwards to try to protect frontbenchers if they possibly can," he said.
He was challenged by two of his former Tory colleagues Sir Patrick Cormack and Bernard Jenkin who suggested, having accepted the findings of the inquiry into his affairs, Mr Conway should not now be questioning it.
Mr Conway said his son Henry had been "paid in the second quartile of the lowest grade" yet had been judged to have been "paid too high".
"I will await with interest any inquiries that are made into the husband of the home secretary who is paid at the top of the highest quarter while being a full-time house husband," he added.
He said the salary scale "remains a mystery to me" and the finding of the committee against him was "not laid down by the House authorities anywhere".
He said the committee's decision against him was different to that made in other cases.
He said "speculation" should apply equally to all MPs and said he had resigned himself to being "the Admiral Byng of this Parliament" - a reference to Admiral John Byng, blamed for the loss of the island of Minorca to the French in 1756, charged with neglect of duty and shot.
His descendants say he was made a scapegoat for the Navy's inadequacies at the time.
But Mr Conway added: "I believe that those members of this House who have employed family members should look a little more closely at how the committee decided about levels of pay ... I don't think for one moment the inquiries into how members employ their staff will end with tonight's debate."