Damian Green

Damian Green

A Conservative MP has been accused by police of "grooming" a Home Office mole over newspaper articles that relied on a series of leaks.

The accusation came as Damian Green was questioned for nine hours by police investigating at least 20 leaks of secret documents from the department. As details of the investigation emerged, the shadow immigration minister told friends he was livid that detectives had resorted to "provocative" language used to describe sex offenders and suicide bombers.

Whitehall officials fear that at least 20 confidential papers are believed to have been spirited out of the Home Office in the past 18 months, far more than the four leaks linked to Green.

The outcry over Green's arrest left Michael Martin facing the worst crisis of his eight years as Commons Speaker as senior MPs of all parties demanded an explanation over why police had been allowed to raid Green's parliamentary office.

MPs were last night threatening to disrupt the state opening of Parliament today if Martin did not act over the Tory MP's arrest on Friday.

Green was detained by police probing his links to a Home Office official suspected of leaking documents that embarrassed Jacqui Smith, the Home Secretary. The episode has led to protests from across the political spectrum that Green was being pursued just for doing his job of holding the Government to account. Smith is also under fire from Cabinet colleagues for her handling of the affair.

Party sources revealed the aggressive questioning that Green faced during his grilling in Belgravia's high-security police station. One source said: "He was accused of grooming a civil servant. He was very angry about the choice of word and did not reply to the question. He thought the police were being deliberately provocative." Green was questioned by police investigating whether he incited the Home Office official - named as Chris Galley, 26 - to leak documents.

Smith refused to apologise for the arrest as she signalled that the investigation was wide-ranging.

But Harriet Harman, the Commons leader, struck a more conciliatory note. She said she was "very concerned" by the police action and called on Speaker Martin to examine the procedures for allowing raids on parliamentary offices. "We have got to be sure that while MPs are not above the law, that actually they are able to get on with their job without unwarranted interference by the law," she said.

The Speaker's critics, joined yesterday by the former Cabinet minister Kenneth Clarke, are demanding an explanation over why the raid was allowed in the Commons. Richard Bacon, a Tory MP, said: "It leaves me wondering how I can have any confidence that the Speaker would defend my right as a member of Parliament to hold sensitive information without the fear of a police raid."