Virenda Sharma could be dragged into a probe by the parliamentary sleaze watchdog after signing a letter from a Labour colleague amid claims it was used to try to influence a court case.
The Ealing Southall MP may face an investigation after fellow MP Keith Vaz asked the Parliamentary
Commissioner for Standards to look into his own behaviour.
It follows a political storm over a letter signed by both men asking the High Court to review a case involving lawyer and Labour Party donor Shahrokh Mireskandari, who is allegedly a friend of Mr Vaz.
The controversy led to a war of words between the MP and Southall councillor Gurcharan Singh after Mr Sharma was accused of putting his name to a letter as a favour for Mr Vaz, who was on the panel which originally picked him as a parliamentary candidate.
Councillor Singh said: "There is a huge question mark over Mr Sharma's behaviour. If Mr Vaz has used his position to intervene in a court case for a personal acquaintance, then Mr Sharma also inappropriately helped out a mate.
"Mr Sharma is a seasoned politician of more than 25 years standing, yet he apparently signed a letter at the request of a powerful Labour colleague without bothering to ask the most basic questions."
Mr Sharma dismissed the accusations as "a childish and irresponsible statement" from a "detractor of the Labour Party" who had defected to the Tories during the Ealing Southall by-election.
Defending his decision to sign the letter to the court, Mr Sharma said: "I had no relationship or knowledge regarding those involved.
"I signed the letter, which was a straightforward letter that we both agreed should be forwarded. There was no reason to ask any questions and I took the letter in good faith.
"I'm sure Mr Vaz is confident he has done nothing wrong and it's up to the commissioner to decide."
A spokesman for the standards commissioner said a letter from Mr Vaz had been received but would not confirm whether an investigation would be launched.