On 24 February 2008, John Lyon, the Parliamentary Commissioner for Standards, was asked by the Taxpayers' Alliance to investigate whether Martin had abused parliamentary expenses and allowances. Lyon was obliged to examine all such complaints although the Commissioner could have ruled that the complaint was unfounded. This followed a week in which Martin's spokesman, the veteran Whitehall communications chief Mike Granatt of PR agency Luther Pendragon, resigned after admitting that he had unwittingly misled "The Mail on Sunday" over more than £4,000 in taxi expenses incurred by the Speaker's wife, Mary Martin. Granatt blamed unnamed officials, but not the Speaker, for falsely informing him that the expenses were legitimate because Martin's wife had been accompanied by an official on shopping trips to buy food for receptions. In fact, her housekeeper had accompanied her; catering for such receptions is the responsibility of the parliamentary caterers.