Former police officer Mark Kearney said his life was in danger after claims he bugged MP Sadiq Khan were leaked.

The retired detective sergeant was thrown into the spotlight after it emerged he recorded the Labour MP at Woodhill Prison in Milton Keynes.

Chief Surveillance Commissioner Sir Christopher Rose is investigating claims that conversations between Mr Khan and terror suspect Babar Ahmad were bugged.

Shadow Home Secretary David Davis accused Justice Secretary Jack Straw and Home Secretary Jacqui Smith of losing control of their departments. He said the case raised serious questions over who was responsible for surveillance in the UK.

Mr Kearney, a former Thames Valley police officer, claimed the Metropolitan Police put him under pressure to record the conversations in 2005 and 2006. Police are allowed to monitor prisoners but conversations between MPs and their constituents are protected from eavesdropping.

Speaking about how his name became public, he told the BBC: "I believe it puts my life and safety at risk. I would also like to say I am quite prepared to co-operate with any inquiry so it can reach a proper conclusion."

The former police officer, who was based at the Milton Keynes jail, faces trial on unconnected charges of leaking information to a local newspaper reporter. He will appear at Kingston Crown Court next week alongside three other people, including the reporter, to enter a plea.

Meanwhile, Labour angrily demanded an apology from David Davis after he said that the MPs bugging row had made a "liar" out of Gordon Brown.

Mr Davis said that the disclosure that a conversation involving Labour MP Sadiq Khan had been secretly recorded by police undermined assurances by the Prime Minister that MPs were not bugged. "This is a very serious issue. It is a breach of a Prime Ministerial undertaking to Parliament and makes the Prime Minister a liar, basically," he told the BBC.

The Leader of the Commons Harriet Harman insisted that there was no justification for such claims and called on Mr Davis to apologise.