The poster, produced by Immediate Sales, the M&C Saatchi subsidiary, appears to show the prime minister confronting his chancellor. It follows claims in a new book, Brown's Britain, by the journalist Robert Peston, which alleges that Brown told Blair: "There is nothing that you could say to me now that I could ever believe."
The Tories believe their advertising can help convince the public that the relationship between Brown and Blair is damaged beyond repair and that the Government is being affected by it.
A Tory official said: "To have an endorsement from the chancellor of a key Conservative message is a gift to our party."