Damian Green, Conservative spokesman on terrorism was arrested yesterday and questioned for nine hours. His home and his offices – in Parliament and in his constituency – were searched before he was bailed with out being charged.

Look at the following sentence from BBC News online.

Police say Mr Green was held on suspicion of “conspiring to commit misconduct in a public office” and “aiding and abetting, counselling or procuring misconduct in a public office” – an obscure and little-used offence under common law.

The “misconduct” appears to be leaking information and aiding and abetting civil servants to do the same. There seems to have been no suggestion that he leaked any information which breached national security – he could have been charged under the Official Secrets Act if he had.

Looking at the material gathered in the Telegraph showing what Damian Green has released to the media in the past few months there is plenty in there which could embarrass the government, but nothing which could threaten national security.

It is true, of course, that a civil servant who leaks to the media or the opposition is committing misconduct. It is a breach of his or her terms and conditions of employment. But this would be true of any material. Oppositions – including, of course, Labour, when it was in opposition, have always thrived on leaks, without any suggestion that this was illegal.

So, who gave the order?

The Prime Minister, the Home Secretary, and the Home Office Minister responsible for terrorism policy all deny that they were consulted about this or knew in advance about the arrest. But Mayor of London, Boris Johnson, Conservative Leader, David Cameron, the Speaker of the House of Commons, and the Serjeant at Arms of the House were all apprised in advance. So the police told the Opposition, but not the Government? Really?

The order could certainly have come from Metropolitan Police Commissioner, Sir Ian Blair (no relation). Today is his last day in office. He was forced out by Boris Johnson soon after the Conservatives won the mayoralty for the first time. Though the details of his differences of opinion with Johnson have not been made public, I would have sacked him for the disgraceful behaviour of the Met during its trial over the shooting of Jean Charles Menezes, an innocent and unarmed man whom they mistook for someone else. The police presented a doctored photograph purporting to show – and actually exaggerating – the resemblance between Menezes and Husain Osman, the terror suspect for whom he had been mistaken. Doctoring the evidence is, to my mind, utterly unforgivable.