By Liz Stephens
Business secretary Lord Mandelson launched a blistering attack on the BBC this morning over its handling of an interview with Gordon Brown on the weekend.
The prime minister was asked during an interview with BBC commentator Andrew Marr whether he was reliant on prescription drugs to help him "get through".
The prime minister denied the rumours saying: "No. I think this is the sort of questioning which is all too often entering the lexicon of British politics."
In a GMTV interview this morning Lord Mandelson let rip at the corporation for popularising right-wing smears on the prime minister.
"We have seen out there on the internet, the blogosphere, all these extreme right-wing people trying to put these smears and rumours about, all completely groundless," he said.
"Frankly, the only surprising thing about all this is that the BBC of all people should choose to give it credibility."
Former cabinet minister, Caroline Flint also defended the prime minister against the rumours: "I don't think there is any truth in this gossip and I think it is really quite despicable.
"I think it is just very unhelpful in politics to have that sort of smears and innuendoes put about," she said.
Later, in an interview with BBC news, Lord Mandelson berated the corporation for "lazy journalism" after he was allegedly misquoted as saying he would work under a Tory government.
The lead up to Labour party conference has been peppered with personal attacks and embarrassing questions for the prime minister.
Last week, former home secretary Charles Clarke unleashed his latest salvo against the Labour leader, insinuating in an interview that Mr Brown may step down before the election due to ill health.
Mr Brown was also asked in a US TV interview whether he was going blind.