The deputy prime minister has called for the former ambassador to Washington Sir Christopher Meyer to resign as head of the Press Complaints Commission.
Sir Christopher described several ministers as "political pygmies"
Sir Christopher has published a book containing scathing remarks about John Prescott and other senior politicians.
In a letter to the former diplomat, Mr Prescott accuses him of the sort of behaviour he should be protecting the public from as head of the PCC.
However, Sir Christopher said he would continue doing the job impartially.
His book, DC Confidential, serialised in several national newspapers, covered the period from 1997 to 2003, and comments on the build up to war with Iraq.
In it, Sir Christopher described several Cabinet ministers as "political pygmies" .
He described Mr Prescott arriving "at the embassy like a mastiff with his hackles up".
And he noted the deputy prime minister "never appeared to be sufficiently up on these (foreign policy) issues".
At one meeting with a senator about the former Yugoslavia, Mr Prescott is quoted talking about war in the "Balklands" and "Kovosa".
Mr Prescott's letter of retaliation is reported in The Observer.
He writes: "How can I or others criticised in your book come to the PCC in future and expect impartiality when you have made it clear you are anything but?
"How can you now hope to be an 'honest broker' at the PCC if people suspect they may feature in any future literary effort on your part?"
Mr Prescott adds: "I am alarmed that you are perfectly happy to profit from tittle-tattle, betraying confidences and by character assassination - the kind of behaviour you at the PCC should be protecting the public from."
He said Sir Christopher was known as the "red socked fop" on Capitol Hill.
In response, Sir Christopher said: "There is work to be done on the PCC. I have enjoyed my two-and-a-half years.
"I am pleased that my contract has been renewed for a further three years. I am confident I can continue to do this job independently and impartially and effectively."
The Observer says Sir Christopher will keep the profits from sales of his memoirs while a chunk of the cash he received for its serialisation will go to the children's charity his wife is in charge of, Parents and Abducted Children Together.
Foreign Secretary Jack Straw has already called on the former diplomat to quit his job at the PCC.