Terrific Torygraph column by Peter Oborne.

In the careers of all prime ministers there comes a turning point. He or she makes a fatal mistake from which there is no ultimate recovery. With Tony Blair it was the Iraq war and the failure to find weapons of mass destruction. With John Major it was Black Wednesday and sterling’s eviction from the Exchange Rate Mechanism. With Harold Wilson, the pound’s devaluation in 1967 wrecked his reputation.

Each time the pattern is strikingly similar. Before, there is a new leader with dynamism, integrity and carrying the faith of the nation. Afterwards, the prime minister can stagger on for years, but as increasingly damaged goods: never is it glad, confident morning again.

David Cameron, who has returned from Afghanistan as a profoundly damaged figure, now faces exactly such a crisis. The series of disgusting revelations concerning his friends and associates from Rupert Murdoch’s News International has permanently and irrevocably damaged his reputation.

Until now it has been easy to argue that Mr Cameron was properly grounded with a decent set of values. Unfortunately, it is impossible to make that assertion any longer. He has made not one, but a long succession of chronic personal misjudgments.