Conservative Party chairman Grant Shapps was widely pilloried after posting an image on Twitter claiming cuts to bingo and beer taxes would "help hard-working people do more of the things they enjoy".
But according to reports, the image was designed on Treasury premises and signed off by the Chancellor, Tory election supremo Lynton Crosby and the Prime Minister's political secretary, Stephen Gilbert.
An unnamed Tory MP said: "It is ridiculous that Grant Shapps has had to take the blame."
Shadow Cabinet Office minister Michael Dugher has now written to Treasury Permanent Secretary Sir Nicholas Macpherson asking who was at the meeting that approved the advert.
Mr Dugher said: "We now learn that this patronising piece of Tory propaganda, which described working people as 'they', was made in the Treasury and approved by George Osborne himself."