The head of the anti-bullying charity, the National Bullying Helpline, has said that she has "absolutely not" accused Gordon Brown of bullying.

Interviewed by Today presenter John Humphrys, Mrs Pratt added that "three or four" people working in and around Downing Street had contacted the organisation in recent years, two of them from the deputy prime minister's office. But she she said there had been no accusations against Gordon Brown himself.

Mrs Pratt said that she decided decided to go public because she was concerned about Mr Brown's denial.

Labour MP Anne Snelgrove, who has been Gordon Brown's Parliamentary private secretary since last June dismissed the allegations, saying that she looked forward to going to work at Number Ten in the morning. She said that there was "a really nice atmosphere" in the prime minister's office, but one which "can get tense" because of the stresses and strains which go with the job.

The allegations against MR Brown stem from a book by Observer political commentator Andrew Rawnsley that includes accounts of the Prime Minister pulling a secretary from her chair, "roughly shoving" an aide, and four-letter word rants that frightened staff.

In extracts published yesterday by the newspaper, Mr Rawnsley said Cabinet Secretary Sir Gus O'Donnell was so concerned that he delivered a "verbal warning" to the Prime Minister, a claim the Cabinet Office said was "completely untrue".