Dec. 4 (Bloomberg) -- Home Secretary Jacqui Smith said she asked police to find the source of documents that leaked from her office because the U.K.’s national security was at risk, brushing off suggestions the probe was a political attack.

“Faced with what appeared to be the systematic leaking of classified information over a sustained period” it became “essential to request police assistance,” Smith told the House of Commons in London today.

The remarks add fuel to a dispute between the government and Conservative opposition over a raid on a lawmaker’s offices last week, which prompted members of Parliament from all parties to lament that their centuries-old liberties were being eroded.

The search of an office in Parliament was unprecedented. Since King Charles I sparked a civil war by taking soldiers to Parliament in 1642, lawmakers have expected to be left unmolested by the law while carrying out their duties. That war ended with Parliament’s forces defeating the king’s, and Charles was beheaded in 1649.

Police on Nov. 27 arrested Damian Green, a Conservative member of Parliament who publicized documents suggesting the Home Office is failing to cope with illegal immigrants, and held him for nine hours while seizing computers and mobile phones from his office in the House of Commons.

Tarnished Reputations

Smith’s account of her involvement in the incident was aimed at deflecting criticism away from Prime Minister Gordon Brown’s government and back onto the Conservatives. While police and lawmakers have their own inquiries into the matter, the raid is threatening to tarnish the reputation of everyone involved including Smith, House of Commons Speaker Michael Martin and the head of the Metropolitan Police.

Conservatives said the raid was an attack on their constitutional duty to question government policies and to reveal shortcomings of ministers including Smith.

The probe was “heavy-handed and incompetent at best,” said Dominic Grieve, the Conservative Home Office spokesman who oversaw Green’s work for the party. At worst, it was “an unwarranted assault on our democracy,” he said, adding that, “This episode has nothing to do with national security and everything to do with political embarrassment.”

Green, 52, had embarrassed the Home Office -- which oversees police and immigration matters -- by publicizing documents showing that a recession would lead to a rise in crime and that it had cleared 5,000 illegal immigrants to work as private guards, one as a janitor in Parliament.

Police Search

Police searched Green’s offices and homes in London and Kent in Southeast England, confiscating his mobile phone, Blackberry and computers. The police say they were investigating whether Green was conspiring to “commit misconduct in a public office” by encouraging leaks.

Smith said today that the investigation was ordered by the Home Office and that no minister in that department was involved in the decision to arrest Green or search his offices.

“The systematic leaking of government information raises issues that strike at the very heart of our system of governance,” Smith said. “It drives a coach and horses through the Civil Service Code, which states that civil servants should act ‘in a way that deserves and retains the confidence of ministers.’”

Conservative View

Conservatives and some lawmakers from the ruling Labour Party question why Martin, who as speaker is ultimately responsible for security in the House of Commons, allowed police to search Green’s office without a warrant.

Martin said yesterday that he wasn’t told about the raid until after it happened and that his deputy, Sergeant at Arms Jill Pay, allowed police to enter.

Smith, who is taking the brunt of the opposition attacks, last night refused to say she had confidence in Martin’s handling of the incident. Brown, while saying the government wasn’t told about the attacks, rebuffed suggestions that Martin should resign and said Smith is right to allow the police probe.

“I’ve got a great deal of confidence in the speaker,” Brown said on BBC Radio 5. “He’s got a difficult job. The speaker isn’t “like a government minister that we support or don’t support. He is appointed by the whole House of Commons.”

Brown also said it would be inappropriate for him to intervene in the affair because “it’s up to the police to follow this through.”

Grieve said that the fact that he was able to obtain confidential documents suggests “a systematic breakdown in trust between officials and ministers arising from the home secretary’s willingness to conceal failings in her department.”

To contact the reporters on this story: Mark Deen in London at markdeen@bloomberg.net

Last Updated: December 4, 2008 11:04 EST