Jacqui Smith faced renewed pressure last night after the secrets case against Damian Green was thrown out and the leaks with which he was involved were deemed not to have involved national security.

The Home Secretary will appear in the Commons on Monday for a statement on a series of issues including the recent terrorism raids in the North of England.

But, after an Easter recess in which she has come under growing criticism over her parliamentary expenses, Ms Smith will face fierce questioning over yesterday’s verdict that some of the leaks obtained by Mr Green were in the public interest. She, too, had raised worries over national security. She mounted a counter-attack last night, declaring that a failure to mount a leaks investigation would have been irresponsible.

Whitehall sources unleashed an extraordinary salvo at Christopher Galley, the civil servant who leaked to Mr Green but was also freed from the threat of criminal prosecution. One labelled him a “complete loser”. Claiming that he had used a term from Star Trek as a computer log-in, an insider said: “That says it all, doesn’t it. The guy was a laughing stock.”

But Ms Smith was again under fire over a police investigation that prompted the spectacle of the Shadow Immigration Minister being arrested, and threatened with serious charges, along with Mr Galley.

The Crown Prosecution Service ruled that there was insufficient evidence to bring a court case against Mr Green, who welcomed the decision and attacked the Government as authoritarian. Mr Green said that officials had felt the need to call in Scotland Yard because of the embarrassment to their political bosses by a string of damaging headlines.

He stopped short of accusing Ms Smith of direct involvement, but said that the affair was the result of the “atmosphere” caused by ministerial anger over the leaks, and said that ministers should take full responsibility.

Mr Green said he was very pleased that he would not face charges, and that publicising the leaks was the job of opposition. “There were no national security implications of any of the information that I obtained,” he said. “All the things that I put in the public domain were legitimate stories showing that our borders are not safe.”

But Home Office sources drew attention to the DPP’s conclusion — that a police investigation was “inevitable” because of the pattern of the leaks and the damage they were doing. They said that both the DPP’s statement and an imminent internal investigation suggested that Mr Green’s actions had fallen below those expected of an MP. “He’s not emerged from this whiter than white. His crowing has been premature,” they said.

Ms Smith said that she had a responsibility to keep information safe. “My job is to protect the British people. It is also to protect the sensitive information about how we protect them.”

The leaked material included the disclosure that Ms Smith failed to tell the public that up to 11,000 security guard licences had been granted to illegal immigrants. Another memo showed that an illegal immigrant had been employed as a cleaner in the House of Commons. Also leaked was a draft of a letter to Downing Street from Ms Smith warning that the recession could lead to rising crime levels.

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