In other words, Miliband tried to construct a winning coalition as a child tries to build a house out of Lego. He would take bricks from his toy box — the Scots here, the intelligentsia, the Northern working class and selected ethnic minorities there — and place them on top of each other until his 35 per cent strategy was complete. So confident was he that, even on election night, when his house was crashing around him, he still thought he could win.

One Labour adviser, who was far too intelligent for Ed Miliband to talk to, said the party forgot that modern left-wing politics isn’t like building with Lego but playing with magnets. The groups you try to pull together into your coalition are just as likely to repel as attract each other.

This is why the calls for Labour to return to Blairism are not quite as convincing as they sound. The old saying “you can win from the centre-Left but not from the Left” remains as true as ever, of course. Equally obviously, it would help Labour if it had leaders who talked to the voters as if they came from the same human species — or if that is too much to ask, from close relatives among the higher primates. But if Labour in England move to the centre, the SNP will use its “Blairism” against it in Scotland. If it tries to reclaim some of the hundreds of thousands of supporters it lost to UKIP, it will alienate supporters in the ethnic minorities. If it carries on pandering to conservative religious minorities by segregating women at Labour hustings, it will carry on losing the support of those, including liberal Muslims, who find its endorsement of reactionary prejudices intolerable. If it concentrates on England, as it must when it has just one seat in Scotland, it will further help the SNP.

A way out will be found only if Labour and the wider Left stop being so dishonest, and I include myself in that criticism. After the election, I looked back on what I had written about Labour with embarrassment. I produced a couple of disobliging pieces about Miliband. But I did not campaign against him. I did not scream at the parliamentary Labour party that he would let the Tories in, and millions would suffer as a result. Nor did many others in the left-wing press. People who knew better stayed silent in part because we did not want to be accused of treacherously aiding and abetting the Conservative cause, and in part because we believed the opinion polls, and thought that somehow or other Labour could cobble together a government. Living in London aided self-deception. Immigration and the extortionate cost of housing is pushing its population leftwards, as is London’s arrogance. The capital is strong and self-confident; it makes the mistake of thinking that everywhere else thinks as London thinks.

If the left-wing press was not pulling the Labour party back towards sanity, then nor were Labour politicians. They stayed loyal too and kept themselves wrapped in a warm cocoon. It ought to shame them that in the years before an appalling defeat not one senior figure tried to overthrow Miliband. Not one even developed an alternative political programme Labour could adopt after defeat. The trade unions were as bad. They have often been a stabilising force in Labour history, but are now so mad that Len McCluskey, the general secretary of Unite, backed Lutfur Rahman, the former mayor of Tower Hamlets, who was not only an opponent of the Labour party but a demagogue whose electoral frauds provoked the courts into removing him from office.

As they face the consequences of defeat, men and women who have spent years avoiding self-criticism will need to understand where they went so badly wrong. They will need to make their choices clear to an electorate which barely heeds them. And they will need to get on with it. Because unless the Left snaps out of its trance, the Conservatives will be in power for another decade.