The Speaker of the House of Commons expressed regret over the police raid on Damian Green’s office yesterday — and blamed officials for failing to tell him that they did not have a warrant.

Michael Martin survived the return of the Commons but put his Serjeant at Arms in the line of fire when he gave a long-awaited account of his role in the Tory frontbencher’s arrest.

Mr Green, who remains on bail, used parliamentary privilege to criticise the police handling of the investigation of leaks from a Home Office official.

But, as Jacqui Smith, Home Secretary, prepares to make her own statement to MPs today, Scotland Yard insisted that it would not be deterred. A senior source said: “This was no knee-jerk reaction. We took a considered view and made a considered decision and our actions suggest that we are investigating significant offences.”

Sir Paul Stephenson, acting Metropolitan Police Commissioner, said that the case potentially touched on matters of national security and his detectives would continue to follow the evidence without “fear or favour”.

The Speaker singled out the police for criticism as he sought to explain why they were allowed to raid Mr Green’s Commons office. Mr Martin said that he did not “personally authorise” the search although he admitted that he had been told in advance.

He told angry MPs that the police advised Jill Pay, the Serjeant at Arms, on Wednesday that they were on the verge of arresting an MP but did not disclose his identity. She told him of the imminent arrest but not the full details. “I was not told that the police did not have a warrant. I regret that a consent form was . . . signed by the Serjeant at Arms without consulting the Clerk of the House,” he said.

“I must make it clear to the House that I was not asked the question of whether consent should be given or whether a warrant should have been insisted on,” he said. “I did not personally authorise the search.”

Mr Martin sought to win further relief from his critics by announcing that a committee of senior MPs would review the raid and set new rules. Harriet Harman, Leader of the House, said further raids would need the authorisation of a High Court judge.

However the Government was given notice of further trouble on the matter. Bill Cash, Conservative MP for Stone, raised an early objection to government moves to delay the review by MPs of the Green affair until after the conclusion of all legal matters.

Although there was no direct challenge to the Speaker’s authority, a series of points of order immediately after his statement suggested that his position was not yet secure.

Mr Green said he accepted that MPs were not above the law but added: “Those who have the real power in this country — ministers, senior civil servants, the police — are also not beyond the law and beyond scrutiny. An MP endangering national security would be a disgrace. An MP exposing embarrassing facts about Home Office policy which ministers are hiding is doing a job in the public interest.”

Michael Howard, a former Tory leader, and Sir Menzies Campbell, a former Liberal Democrat leader, led a cross-party chorus of disapproval. And last night the Conservative MP Richard Bacon called on Mr Martin to resign, saying: “It was a lamentable and shocking performance. He has failed in his fundamental duty to protect Parliament and to protect MPs from unlawful search and seizure.”

Mr Martin brought the discussion to a conclusion after about 25 minutes, telling MPs that they could debate the matter in full on Monday. But the affair spilt over into the debate of the Queen’s Speech, with David Cameron and Gordon Brown trading blows.

Mr Cameron was asked repeatedly what he knew of Mr Green’s operation to collect information from the 26-year-old official, Chris Galley.

Mr Brown said: “You cannot pick and choose whether you support the independence of the police. You either support it or you do not support it.”

While working at the Home Office, Mr Galley first approached Mr Green in person in May 2006 to express concern about the way the Immigration Department was being run. The following November he wrote asking for a job in Mr Green’s office.

Until yesterday the Conservatives were refusing to say what discussions there had been about Mr Galley’s career before and after his letter was sent about two years ago.

Last night the party gave a fuller account of the circumstances around Mr Galley’s written job application. A spokesman said: “There was no interview and he was informed in writing that there was no job. A job was never discussed on any other occasion.” The spokesman declined to expand on whether there was any further communicationbetween Mr Galley and Mr Green or the nature of their relationship.

Harriet Harman, the Leader of the Commons, refused to be drawn about whether she still had confidence in Mr Martin.

Who knew what, when

Damian Green Christopher Galley approached the Conservative Party in May 2006, expressing concern about the way the Immigration Department was being run. The following November he wrote to Mr Green, asking for a job, and was turned down without an interview. Mr Green met Mr Galley most recently last September and bought him a drink. Mr Galley was arrested on November 19 and Mr Green on November 27.

Sir David Normington, Home Office Permanent Secretary Sir David is thought to have initiated the leak inquiry after newspaper reports in November 2007 suggested that Jacqui Smith was involved in covering up the licensing of 5,000 illegal immigrants as security guards. He was informed at 1.45pm last Thursday that an opposition spokesman was about to be arrested. It is claimed that this was the first time that anyone in the Home Office was told that an MP was the subject of the police investigation.

Jacqui Smith, Home Secretary Knew that a Home Office leak inquiry was under way and knew in advance of November 19 that one of her civil servants was to be arrested. She has vigorously denied knowing in advance that an MP was the target of the investigation and insists she was only told about the search and arrest of Mr Green afterwards.

Scotland Yard Sir Paul Stephenson, acting Metropolitan Police Commissioner, has confirmed that Sir Gus O’Donnell, the Cabinet Secretary and head of the Civil Service, called the police last October.

The Prime Minister Gordon Brown was aware “in general terms” that there was a leak inquiry under way, and he was informed after the event that both a Home Office official and Damian Green had been arrested. Asked if he was aware that an MP formed part of the inquiry, his spokesman replied “No”.

The Speaker and the Serjeant at Arms Jill Pay was contacted by Met Police last Wednesday – a day before the action – and warned that an unnamed MP might be arrested and charged. She told Michael Martin “in the strictest confidence” and signed a letter giving them access to Parliament the next morning.

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