It was revealed in March 2009 that Cohen had received £104,701 over the previous five years under the Additional Costs Allowance for his Wanstead home based upon the representation that this was his second home. The home that Cohen represented as his primary home was a house in Colchester, despite the fact that Cohen spent very little time at that location and used it only as a holiday home. As his Wanstead home is where Cohen resides both when going to Westminster and attending to his constituency, the claim of the Additional Costs Allowance was criticised as an abuse of an expense allowance intended to help Members of Parliament who need to maintain one home in their constituency and another in London. Cohen responded to criticism by stating that the Additional Costs Allowance was intended to be de facto salary for Members of Parliament.[5][6]
On 30 June 2009 he announced he would not stand for re-election. He said the strain caused by the criticism over his expenses, and the formal investigation into his claims, were the main factors behind his departure.[7]
On 22 January 2010 the Standards and Privileges Committee of the House of Commons published its report into Cohen's expenses and concluded that he had received over £60,000 in expenses to which he was not entitled.[8] The report did recognise that the ill-health of Cohen's wife (she suffered a stroke in 2004[9]) had been a significant factor in the decisions he had made but maintained that he had still committed a serious breach of the rules. The report recommended that Cohen apologise to the House, which he did on 29 January 2010, and that the Resettlement Grant of £65,000, normally paid to Members of Parliament upon retirement, be withheld. The House ratified the latter punishment on 1 February 2010.
