This was the nightmare result that David Miliband's camp - and many other party insiders - most feared: victory for Ed Miliband on the back of a ferocious campaign by three of Britain's biggest unions to thwart the older brother.
Had MPs decided the outcome, as they did in every leadership contest until 1980, David would now be tasting triumph - as he would have done had Labour adopted the straightforward one-member-one-vote system used nowadays by the Conservatives and Liberal Democrats.
Instead Ed's 20% lead among trade union members swamped David's 9% lead among party members and 7% lead among MPs and MEPs.
David would still have won had this been a first-past-the-post election. He led his brother by 3% on first preferences.
However, Ed won the battle for second preferences by just enough to secure the 51-49% victory indicated by our poll for the Sunday Times two weeks ago. On the final count, MPs who had backed Ed Balls supported Ed Miliband over David by a margin of two-to-one. Had they divided evenly, David would now lead the Labour Party.
Overall, the first-preferences supporters of Diane Abbott, Ed Balls and Andy Burnham, divided four-to-three for Ed over David among party members and MPs and by three-to-two among trade unionists.
In his moment of victory, Ed Miliband will have to face down the “red Ed” charge – that he won the election by appeasing the unions and tacking to the Left, which is where his party feels comfortable but the wider electorate does not. The result gives some ammunition to his critics, notably that the supporters of Diane Abbott, the most left-wing candidate divided three-to-one for Ed over David. The most urgent test of Labour's new leader is whether - and if so, how - he seeks to combat the charge that he is in hock to the unions.
Moreover Ed was the first choice of only 32 per cent of MPs (and only three other members of Gordon Brown's final cabinet). Every previous party leader has been the preferred choice of the parliamentary party – either because they alone decided the matter or, since 1983 because their choice was the same as that of the wider party membership. Ed must now win the active backing of Labour MPs knowing that most of them would have preferred to be led by his brother.
One final point is worth noting. If Labour wins the next general election, Oxford’s remarkable dominance of the occupants of 10 Downing Street will continue. It has supplied every graduate to lead their party to victory for three-quarters of a century. Two non-graduates have won elections (Winston Churchill and John Major); otherwise we have to back to 1935 to find a victor who went to any other university (Stanley Baldwin: Trinity College, Cambridge).
It could be that the prospects of Ed Miliband (Corpus Christi College, Oxford) will be shaped less by his bright red politics than by his dark blue education.
This article also appears as a Commentary
Getting it right: How our final predictions measured up against Saturday's final result
