Phone hacking: With friends like these...

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Media captionMr Cameron insisted that he had "no inappropriate conversations" about the BskyB takeover bid

A friend in need is a friend…until they become a massive political headache.

David Cameron has always defended his decision to give Andy Coulson a second chance…to take the man who resigned as editor of the News of the World into Downing Street…to ignore those who warned it was a mistake… until - that is - today.

Declaring that with 20-20 hindsight he would not have offered him the job as director of communications could be seen as a statement of the blindingly obvious.

However it was enough to convince Tory backbenchers that their leader was capable of freeing himself from the hacking quagmire.

It will not satisfy those - including the Labour leader - who say the prime minister closed his ears to repeated warnings that Mr Coulson was at best political trouble and at worst involved in criminal activity. Something he strenuously denies.

Today the prime minister said he believed in an old fashioned principle - innocent until proven guilty - nevertheless he tried to separate his fate from that of his friend.