LONDON (AFP) - British police raided an Opposition lawmaker's parliamentary office without a search warrant, the House of Commons speaker said Wednesday, fuelling angry claims that ministers were behind the move. The revelation was the latest twist to a row over last Thursday's arrest of Damian Green, the main Opposition Conservatives' immigration spokesman, by police probing embarrassing leaks to newspapers from the Home Office. It came as Speaker Michael Martin, a member of Prime Minister Gordon Brown's ruling Labour Party whose office requires him to be politically impartial, made an extraordinary statement to an angry, noisy House of Commons. Several lawmakers, mainly Conservatives, have publicly questioned Martin's authority in recent days by saying he should have stopped Green's office being searched. "I did not personally authorise the search," Martin said. "I was not told that the police did not have a warrant... "I have been told that the police did not explain as they are required to do that the sergeant (a senior parliamentary official) was not obliged to consent or that a warrant could have been insisted upon." Martin said he was appointing a committee of seven senior MPs (members of parliament) to report on the issue and that lawmakers would debate it Monday. A senior police officer is also drawing up a report. The Speaker's statement drew jeers from Conservatives, who usually conceal any unhappiness they may feel with his decisions because he selects which lawmakers can speak in debates. Green was arrested during a probe into Home Office leaks which led to newspaper stories including that an illegal immigrant worked as a cleaner in parliament and that illegal immigrants were working as security guards. The move has prompted furious Conservative claims that Brown's Labour Party, which has been trailing the Conservatives in opinion polls for months, may have been behind the "Stalinist" move. But Home Secretary Jacqui Smith, who is in charge of the police, has declined to apologise, saying she was unaware Green would be arrested until after it happened. Speaking in response to Martin's comments, Green suggested the government had been trying to silence him following a series of embarrassing leaks to newspapers from the Home Office. "An MP (member of parliament) 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," he said, to raucous cheers from fellow Conservatives. "The day when exposing facts which ministers would prefer to keep hidden becomes a crime would be a bad day for democracy in this country." John Reid, a home secretary under Tony Blair, referred to the time in 2006 when Blair was questioned over the "cash for honours" inquiry into claims Labour donors were rewarded with seats in upper chamber the House of Lords. Responding to the statement, he said it was important that "the principle of the independent operations of the police is reasserted in all of this, as indeed it was during investigations into the prime minister and his staff. "Some of these points would carry a little more weight had they been raised during that period."