A Home Office "mole" who leaked documents to a Tory frontbencher has said he acted in the public interest.

Civil servant Christopher Galley, 26, admitted giving "embarrassment material" to immigration spokesman Damian Green, who was arrested and held for nine hours after the leak was discovered.

In a statement, his lawyer Neil O'May said: "Christopher Galley first met Damian Green in the Houses of Parliament in 2006. He was in contact with Mr Green over the following two years, including further meetings with him.

"Mr Galley gave Damian Green information which was important for the public to know in an open and democratic parliamentary system.

"As a shadow minister for immigration and as a Member of Parliament, Damian Green received the information in the same spirit and used it in his parliamentary duties.

"In providing this information for a shadow minister, Mr Galley believed that it would be used in a highly responsible manner in the public interest."

Mr O'May said leaked documents were "embarrassment material" important in holding the Government to account but added: "It's really not state secret, national security, terrorism, financial jeopardy, loss, gain or otherwise - nothing remotely like that."

The lawyer denied Mr Galley had agreed to help police entrap Mr Green after his own arrest in a dawn raid by the anti-terrorism officers at his home on November 19 this year.

Mr Green, who denies all wrongdoing, was arrested last week and is on bail pending further questioning in February.

Commons Speaker Michael Martin has announced he will make a statement on Wednesday regarding a police raid on Mr Green's Parliamentary office.

Politicians from all sides have condemned the police action against Mr Green, with former Labour minister Denis MacShane dubbing it "a mammoth breach in the core democratic doctrine of parliamentary privilege".

Commons leader Harriet Harman said there needed to be an urgent review of procedures to ensure the protection of "big constitutional principles".

She said: "We have got to be sure that whilst MPs are not above the law, that actually they are able to get on with their job without unwarranted interference by the law. These are very, very big constitutional principles, we have to make sure they are protected."

Home Secretary Jacqui Smith said officers are investigating a "systematic series of leaks" of potentially sensitive Home Office material and must be allowed to "follow the evidence where they need to" without interference from the Government.

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