Labour MP Harry Cohen is under investigation by Scotland Yard for allegedly receiving more than £70,000 in expenses for a second home in Colchester.
Mr Cohen, the MP for Leyton and Wanstead, was strongly criticised by a Commons committee for receiving money for his second home while he rented out the property he had previously claimed was his main home.
The Commons committee recommended that Mr Cohen, who is standing down as an MP at the forthcoming general election, should lose his £65,000 retirement payment.
Mr Cohen, as an MP living in outer London, could have claimed the £9,000 London supplement, instead of the second home allowance.
