PM 'must denounce Tory's arrest'

The Prime Minister has declared that the decision to question Damian Green and search his home and offices was "a matter for the police" and of which he had no prior knowledge.

But amid mounting anger and disquiet at Westminster over the action, taken in relation to alleged leaks of sensitive Home Office material, Mr Cameron said the PM had a duty to speak out.

Writing in the News of the World, he said: "When it comes to vigorous opposition, if this approach had been in place in the 1990s, then Gordon Brown would have spent most of his time under arrest.

"He made his career from passing on Whitehall leaks. And he'll be guilty of hypocrisy if he doesn't speak out," he said, - insisting the arrest was "not about our national security but government embarrassment".

He wrote: "The Prime Minister has simply repeated that he 'had no prior knowledge' and this is 'a police matter'. Frankly, that's not good enough.

"The question is: does he think it is right for an MP who has apparently done nothing to breach our national security - and everything to inform the public of information they're entitled to know - to have his home and office searched by a dozen counter-terrorist police officers, his phone, Blackberry and computers confiscated, and to be arrested and held for nine hours?"

Mr Cameron also turned his fire on the Commons authorities for apparently "not thinking twice" about allowing officers to raid his immigration spokesman's office in Parliament.

Speaker Michael Martin has faced calls for his resignation over the matter but his office would only say that "there is a process to be followed and that was followed" but the Home Office confirmed permission would have been required from the House authorities.

While not criticising the present Speaker directly, Mr Cameron pointed to the example of his 17th century predecessor William Lenthall, who famously refused to give up MPs to King Charles I when he entered the Commons to have them arrested.