British Prime Minister Gordon Brown has come under pressure after an anti-bullying charity chief claimed it had been contacted by the staff from his office, amid allegations about his violent temper.
But his ruling Labour party, mindful of the upcoming election, went into an offensive, with his top aide calling for evidence to be made upfront.
National Bullying Helpline chief executive Christine Pratt alleged that three-four contacts had been made by the 10 Downing Street staff in recent years.
A new book by leading journalist Andrew Rawnsley has claimed that Brown had grabbed a staff member by lapel and shouted at him, punched the back of a car seat after receiving a bad news and repeatedly swore at advisers.
Brown's woes were compounded when The Observer newspaper reported that civil service head Sir Gus O'Donnell had warned the Prime Minister about behaviour towards staff.
Reacting to the claims in the book Brown said he had "never hit anyone in his life".
Things were sometimes said "in the heat of the moment", but "I have never hit anyone in my life," Brown said in an interview to 'Channel 4 News'.
"If I get angry, I get angry with myself... I throw the newspapers on the floor or something like that, but please," Brown said.