The civil servant at the centre of the Damian Green leak inquiry row broke cover yesterday as his lawyer said that he had acted in the public interest.

Christopher Galley, 26, appeared nervous and remained silent as he sat alongside his lawyer Neil O’May, at a press conference in London.

Mr O’May sought to increase pressure on the police to drop the investigation, questioning whether it was “necessary and proportionate”. “If ever there was a case of ’don’t shoot the messenger’, this is surely it,” he said.

The former Conservative council election candidate had first met Mr Green in the Houses of Parliament in 2006 and “regularly” supplied him with information for the next two years, Mr O’May said.

In a carefully worded statement that did not address the question of whether the civil servant was directed to leak specific information, the lawyer said that information 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.” He denied that Mr Galley had been knowingly used by police after his arrest in an attempt to entrap Mr Green.

Mr Green was Mr Galley’s “only contact” in the House of Commons, Mr O’May said, but he refused to say whether he had met other Tory frontbenchers during the time he was leaking information.

Mr Galley was arrested “in a dawn raid by the anti-terrorism officers at his home on November 19 this year”, Mr O’May said.

He was held and questioned and volunteered the whereabouts of his computer, mobile phone and the documents the police were interested in, Mr O’May added.

Mr O’May insisted the leaked documents were “embarrassment material” and important to holding the Government to account. “It’s really not state secret, national security, terrorism, financial jeopardy, loss, gain or otherwise — nothing remotely like that,” he said.

He declined to comment on how Mr Galley would plead if charged with any offence. “We haven’t reached that stage,” he added. “Let’s hope he’s not charged with anything.”

Asked why police were not using powers granted to them under the Official Secrets Act, he said: “Instinct is to say that it is because the material that was passed across was at the very lowest level, the sort of thing that was almost in the public domain already.”

Mr O’May, a partner of Bindmans who represented Lord Levy in the cash-for-honours investigation, refused to say who was paying for Mr Galley’s legal representation.

Times Recommends

• What makes the perfect mum?
• To keep me stress-free, no more awareness days, please
• What do lottery winners buy?