British Prime Minister Gordon Brown said he has "never, never" hit anybody as his office dismissed media allegations of staff intimidation which have threatened his pre-election fightback.

Mr Brown admitted to a few solid tackles on the rugby pitch in his youth and throwing newspapers on the floor but said any anger was largely directed at himself, as he geared up for a general election expected in May.

"If I get angry I get angry with myself," the prime minister told Channel 4 television. "I throw the newspapers on the floor or something like that.

"Let me just say, absolutely clearly, so that there is no misunderstanding about that: I have never, never hit anybody in my life."

The Observer newspaper published extracts from a book by columnist Andrew Rawnsley, which contained allegations about Mr Brown's conduct in his 10 Downing Street office.

It alleged there had been a string of incidents, such as shouting and swearing at colleagues and thumping car seats, which had left staff shaken.

The newspaper said that "during one rage, while in his prime ministerial car, Mr Brown clenched his fist in fury after being told some unwelcome news and then thumped the back of the passenger seat."

It added that the protection officer in the seat "flinched with shock" and "the aide sitting next to Brown... cowered because he feared 'that the prime minister was about to hit him in the face'," The Observer added, quoting from an extract.

According to the book, Britain's top civil servant, Cabinet Secretary Gus O'Donnell, told Brown to change his behaviour after reports that his fiery outbursts had frightened staff.

He reportedly told Mr Brown: "this is no way to get things done."

Mr O'Donnell felt the need "to calm down frightened duty clerks, badly-treated phone operators and other bruised staff" and tell them "don't take it personally", The Observer reported.

However, a spokesman for the Cabinet Office said: "It is categorically not the case that the cabinet secretary asked for an investigation of the PM's treatment of Number 10 staff."