Prime Minister Gordon Brown rejected as baseless and malicious allegations published in a Sunday newspaper that he had terrified staff by shouting abuse at them and in some cases had physically intimidated them.

The allegations, contained in excerpts of a new book published in the Observer, put Brown's character at the heart of Britain's political debate in the build-up to an election due by June that the Labour Party is forecast to lose.

"These malicious allegations are totally without foundation and have never been put to Number 10," said a statement from Number 10 Downing Street, the prime ministerial office.

Speculation about Brown's behaviour towards his staff dominated Sunday morning news bulletins and chat shows, knocking off the agenda a major campaign speech he made on Saturday to try and win back voters tempted by the Conservatives.

Opinion polls put the Conservatives far ahead of Labour, who have been in power for 13 years, but in recent weeks the gap has narrowed and Brown is trying to mount a fightback.

But his hopes of capturing the public imagination with his electoral pledges were dashed by the publication of excerpts from a new book by Observer political columnist Andrew Rawnsley.

Among other allegations, Rawnsley wrote that during fits of rage Brown had screamed at staff, grabbed one aide by the collar of his shirt, and thumped his fist into a car seat, causing another aide to cower in fear of being hit in the face.

"I DON'T DO THESE SORTS OF THINGS"

Brown has not responded to the specific allegations made by Rawnsley, but just before the excerpts were published he defended his character, saying he had never hit anybody.

"If I get angry, I get angry with myself," Brown said on Saturday in an interview with Channel 4 television.

Asked whether he swore at staff, threw things or shoved people, Brown said that he threw newspapers on the floor but had "never, never hit anybody in my life."

"I don't do these sorts of things," he said, looking pained.

In separate comments to the Independent on Sunday, Brown tried to make light of the allegations.

"I may have done one or two good tackles at rugby, but the idea that is suggested in this so-called inside account is just ludicrous," he was quoted as saying.

Rawnsley strongly defended his book, saying that it was based on detailed conversations with impeccable sources.

Brown allies including Business Secretary Peter Mandelson and other senior ministers lined up to defend him.

Mandelson dismissed the stories but sought to turn the negative publicity into a positive, arguing that Brown was very demanding both of himself and of people around him.

"He knows what he wants to do. He does not like taking no for an answer from anyone. He will go on and on until he's got a policy or an idea in the best possible form which he can then roll out," Mandelson said in an interview on BBC television.

"On the way, yes, there is a degree of impatience about the man, but what would you like, some sort of shrinking violet at the helm of the government when we're going through such stormy waters?" he said.