The Manchester murders have given British politics its first conspiracy theory with a grain of truth in it. It may sound ghoulish to discuss the political consequences of an atrocity. But terrorism is a political crime, and we are in a general election campaign. Everyone is thinking that the Manchester attack passes the advantage to Theresa May. Soon they will be saying it too.

It is easy to predict how the killings will be knitted into the left’s explanation for the defeat of 2017. Against the odds, Labour was doing well in the polls, Corbyn’s supporters will say. Why one survey had the opposition a mere nine points behind the Conservatives. (Others had it 14 points down, but trust me, they will be forgotten). The Labour manifesto was as well received as a free all-you-can-eat buffet at a party. Meanwhile, the Tories were in trouble. The truth about Theresa May began to emerge in the days before the attack. Far from being the strong and stable leader of Tory propaganda, she was wooden and weak. Worse than that, anyone could see that May and her advisers shared a fatal willingness to do without intelligent advice from their colleagues. They were not just ignorant but proud of their ignorance. Her interview with Andrew Neil showed a flailing, U-turning politician, who seemed alarming ill-prepared for the coming Brexit negotiations. Maybe, just maybe, it showed a beatable politician too.

Then, Salman Abedi attacked a concert for teenage girls and the country rallied behind the prime minister. The soldiers on the streets, the detectives working through the night, the taxi drivers and cafe owners giving free rides and free food to everyone who needed it, all spoke to a mood of national unity in the face of barbarism. Naturally, the nation united behind its leader, and did so for good reason. Theresa May has no experience of economics, foreign policy and international trade, which is why sensible commentators view the Brexit negotiations with dread. But she does know about security.

You don’t have to agree with the dark voices from the cretino-left, who immediately described the attack as a false flag operation, to see the appeal of blaming Labour’s failure on a crime that showed Theresa May at her best and Jeremy Corbyn at his worst. Such fantasies have a history. After Margaret Thatcher’s landslide in 1983, the cretino-left of the day claimed she had incited the Argentinians to invade the Falkland Islands so she could win as a wartime leader. They were dismissed. But even sensible people on the left sighed as they thought that, if only there had been no Falklands War, Thatcher would never have won a second term. Equally, after the murder of Jo Cox last year, the proto-fascists of the 21 st saying that the British state had had her killed to boost the pro-remain vote. They were dismissed in turn. But the supposedly respectable conservative press treated a political assassination with a shocking lack of shock. It showed that its main concern was how Jo Cox's murder might hurt it at the polls. Had remain won, today's Tories would have gone the same way as the leftists of Mrs Thatcher's day.

The mild fantasy about the 2017 election, the polite conspiracy theory, if you prefer, will gain a purchase as Tory rule stretches on for another 10 years. I can see why it will be believed, but that does not mean it should be respected. It ducks the obvious question: why does a terrorist outrage expose Labour’s weaknesses?

Conservative economic policies have been as much a disaster for law and order as they have been for health, education and local government. The failure to raise national productivity and the tax take has forced a reliance on spending cuts that has left the criminal justice system dangerously exposed. May has had to order troops onto the streets because we have just over 5,500 armed police officers in England and Wales, half the number of 15 years ago. Overal, the Conservatives have cut 20,000 police jobs. Theresa May reduced police budgets every year for the five years she was Home Secretary. Hundreds of Islamist fighters are returning from Syria and we do not have the manpower to monitor them.

Think of what a patriotic Labour party could say this week. It could show all due respect to the injured and the families of the dead while attacking the criminal neglect of the criminal justice system.

But Labour is not a patriotic party, or, more accurately, its leaders aren’t patriots. I don’t just mean that Jeremy Corbyn and his supporters inside and outside Westminster don’t love their country. No one should be obliged to express such a creepy and gormless emotion. It’s that they don’t even like it. I have set out at length Corbyn’s connections to the IRA, Iran, Russia, Hamas and Hezbollah. I have denounced at equal length the political nihilism of a post-Cold War left that will excuse religious and secular reactionary forces at home and abroad as long as they are anti-Western. Most people won’t follow the links or care about arguments about basic principles. But they will instinctively know that the current Labour leadership has a Pavlovian tendency to always be on the side of governments and movements that mean them harm.

When Labour’s leaders attacks cuts in police numbers, no one for a moment believes that it would recruit thousands more officers and intelligence agents if they had the chance. When they denounce terrorists in Manchester, no one forgets that they embraced other killers as their 'friends'.

What did the Labour members who voted for Corbyn – not once, lest we forget, but twice – think they were doing? Did they never pause and say to themselves: ‘the voters won’t respond well to his Islamist and IRA friends?” Apparently not. Apparently they either fooled themselves into believing that he could win or didn’t care whether Labour won or not as long as the Labour leadership pandered to their prejudices.

Suicide bomber or no suicide bomber, Labour was always going to lose. The only question is the question that has been there since the party choose to enact its own suicide pact: How badly?