The Chancellor will tack right to unsettle Cameron: this is a good time to buy Browns

One day at the Commons recently, just before Prime Minister’s Questions, David Cameron found himself in the gents next to Gordon Brown. The two said a brief hello and then silence fell. As Mr Brown left, he said to the Conservative leader over his shoulder: ‘Good luck’.

What struck me — beyond the mischievous interpretation that this was a shade disloyal to his own leader — was that it was the first time Mr Brown has sent a message to the Tory leader that their relationship will outlive the premiership of Mr Blair.