And now, in an incautious admission, he has reminded us of his core beliefs – as the proud son of a Marxist academic. He wants to restore socialism to Britain. In spite of everything, the mission of Labour under Ed Miliband is to revive a political belief system that brought Britain to its knees, that blighted the lives of hundreds of millions of people in the former Soviet Union and Eastern Europe, that was responsible for untold murders and abuses of human rights, and that in the past 30 years has been decisively rejected across the planet in favour of liberty, free enterprise and market economics – a rival system that has lifted and is lifting hundreds of millions of people out of poverty and servitude. Someone needs to tell Ed Miliband that socialism failed, and I have just the man to do it.

I happen to think Mr McBride is genuinely repentant, and I know that he is working hard for good educational causes in London. But if he is to achieve full redemption he needs to think about why he behaved in that way. What was it that legitimated – in his mind – this hideous trampling over all norms of decency? He smeared ministers who seemed to stand in his way, he destroyed careers, he wrecked family lives. It seems incredible that a highly intelligent man could act like this just because he adored Gordon Brown. No, that wasn’t enough: he justified his ruthless actions to himself in the same way that socialists have always justified their ruthlessness – that the end justified the means.

And that is the problem with socialism. It has always involved the use of revolting means to pursue an unattainable end. It has seen the rights and liberties of individuals trampled in the name of a collective good. Damian McBride is a small but interesting example of the mental contortions of socialists over the last century, when there is no abuse or tyranny – large or trivial – that has not been justified in the name of the people.

When the Securitate persuaded children to inform against their parents in Ceausescu’s Romania, they knew – at one level – that what they were doing was creepy. But they believed it was in the wider interests of the state, and therefore of the people themselves. When thousands of Soviet dissidents and bourgeois reactionaries were hauled off to perish in Siberian gulags, the authorities knew – with one side of their brains – that this was morally no better than Nazism; but they persuaded themselves that it was for the greater good, and that you could not make an omelette without breaking eggs. When the North Koreans shoot anyone who falls foul of their deranged and psychotic regime, they don’t blame their evil dictator; they think – or at least they assert – that they are protecting a system of government that is morally superior to that of South Korea and the rest of the capitalist world.

I don’t mean that Ed Miliband will try to import some new form of Stalinism to Britain, or that we will see the systematic abuse of human rights. British socialism has always been a much milder strain. But the fundamental impulse is there: to use regulation or coercion to try to impose an idea of equality, when the result is the exact opposite. Why has social mobility declined in the past 30 years? Why is it that there are fewer children from poor backgrounds who make it all the way to the very best universities than there were in the 1960s?

Because – in the name of equality – Labour politicians launched a war against the grammar schools and indeed against the whole competitive ethos in education. How is a dose of socialism going to help us improve our schools, or reform the welfare state, or get a better deal from the European Union? The most important political fact since the crash of 2008 is the complete failure of the Left to provide any realistic alternative to the free market economics that have been adopted across the developing world, and that have seen a huge rise in living standards for billions.

It has its chance to offer a new model – and we have heard nothing. Now we have Ed Miliband telling us that his plan is to go back to Brownite “socialism” – the over-borrowing and over-spending that got us in the mess in the first place. Why hand back the bridge to the very people who ran the ship aground?