"Objecting to the third runway is a handy way of appealing to Labour's left, who will be important in any contest. Mr Miliband came up against his former brother-in-arms Mr Balls. The Schools Secretary, who had no departmental interest in Heathrow, used the same meeting for a brutal assault on Mr Miliband's stance. It was a telling moment.
Mr Balls, 41, did so knowing he had the support of Lord Mandelson. The pair – to the astonishment of observers of the Blair-Brown wars – have forged an alliance since the peer's return to Whitehall from Brussels.
It is one of the most extraordinary reconciliations in modern political history, given the acidity of the briefings they used to put out about each other during Mr Blair's time at Number 10."
"Extraordinary" sure is the right word - particularly as Balls is said to have "begged" Brown not to appoint Mandelson as Business Secretary back in the autumn. But if the Schools Secretary is now counting on Mandy's support in any leadership contest, he'd be advised to remember how swiftly - and how decisively - Mandelson shifted from Team Brown to Team Blair back in 1994.