Daniel Hannan is an MEP for South-East England, and a journalist, author and broadcaster. His most recent book is What Next: How to Get the Best from Brexit.

“Mr Speaker, I am deeply patriotic,” said David Cameron in a sombre voice when he presented the Saville Report to Parliament in 2010. “I never want to believe anything bad about our country. I never want to call into question the behaviour of our soldiers and our army, who I believe to be the finest in the world. But the conclusions of this report are absolutely clear. What happened on Bloody Sunday was both unjustified and unjustifiable.”

Most ConservativeHome readers will share the former Conservative leader’s patriotism; and almost everyone will echo his regard for our troops. We are enormously lucky in this country to have Armed Forces which are lethal when turned against foreign foes but which are not, in general, used for internal repression. Our Service personnel are brave but not bellicose, cheerful but not frivolous, polite but not obsequious, always ready to get stuck in. It is hard to have dealings with British soldiers and not end up liking them.

So of course we are uneasy at the idea of former Paratroopers being hauled through the courts because of something that happened nearly half a century ago. Yet we should never lose sight of what it is we admire about our Servicemen in the first place. We admire them precisely because they are professional and disciplined. We admire them because, unlike their counterparts in much of the world, it is hard to imagine them training their guns on civilians. That is what makes the events of 30 January 1972 so painful.

Bloody Sunday was a catastrophe for the Army. Many Catholics had initially welcomed the deployment of regular troops in Northern Ireland, seeing them as likelier to be impartial than the Protestant-dominated local security forces; but the deaths of 13 unarmed protesters in Londonderry convinced Ulster’s minority community that they could not expect fairness from the British state. Hundreds of young men were driven overnight into the clutches of the IRA, with dreadful consequences for themselves and for others. In the aftermath of the shootings, the British government behaved like some insecure dictatorship, more concerned with the reputation of its security forces than with justice.

It took 37 years for the government officially to acknowledge the truth, namely that there had been both a grotesque abuse of force by some soldiers on the day and a cover-up afterwards. I felt paradoxically proud when Cameron issued a national apology. The desire to get at the facts, however awkward, is a distinguishing characteristic of an open society. Lots of nations in such a position adopt what we might call an anti-Dreyfusard stance, elevating the reputation of their Armed Forces over the right of individuals to redress. I am glad to live in a country where the rights of those who resent it – as most of the young men who died in the Bogside did – count for as much as anyone else’s. My British patriotism does not rest chiefly on the accomplishments of our Servicemen, awesome as they are. It rests on our indignation at injustice, our preference for individual rights over collective identity, and our determination to follow the law.

Once the Saville Enquiry had overturned the previous whitewash, prosecutions became almost inevitable. Now they are reportedly set to go ahead against four of the soldiers accused of acting outside the law that day.

There are various hooks on which opponents of the prosecutions might hang their doubts. They could argue that it is impossible to be sure of justice so long after the event. They could propose that the United Kingdom adopt, as the United States does in some circumstances, a statute of limitations. They could argue, with Gerry Adams, that there should be indemnity on all sides – British Servicemen, loyalist gunmen, Republican paramilitaries. (Martin McGuinness took a different line, contending that the amnesty should not apply to soldiers. It has since been confirmed that McGuinness was the Provisional IRA’s second-in-command on Bloody Sunday, and he eventually admitted that his men had been carrying weapons.)

By and large, though, these are not the grounds on which the Paras’ defenders are taking their stand. Rather, they argue that there is an asymmetry in the way in which the two sides in the conflict are being treated. IRA murderers have benefited from an amnesty, they say, so why should our boys be punished? Shouldn’t we (they continue) take mitigating circumstances into consideration? The Provos were, as McGuinness confirmed, armed that day. They were deliberately seeking to provoke a reaction. The Official IRA, the “Stickies”, actually fired shots (though only, it seems, after the Paras had started shooting). Do these things, ask the soldiers’ supporters, not count for something?

And anyway (they conclude), why this peculiar focus on 13 of the 3,532 victims of the Troubles? What about Bloody Friday? What about Birmingham and Warrington and Shankill and Crossmaglen and a hundred other IRA abominations? Why not spend a fortune on inquiries into them?

The answer, surely, is that our soldiers are not terrorist gangsters. They operate according to rules, and when those rules are breached, there are consequences. The idea of equivalence between the two sides was, paradoxically, a key IRA demand. The Provos gave their men military ranks, and demanded POW status when they were jailed for their crimes. When Adams called for amnesties all round, he was at least being consistent. But I suspect that most ConHome readers always regarded the IRA as a criminal gang rather than as a legitimate army. The reason we must hold our troops to a high standard is the same reason that we are the legitimate government in Northern Ireland, namely the demands of the law.

To be sure, there are arguments for clemency. It is hard to see how any purpose would be served by banging up men in their seventies for offences committed when they were very different people. That, though, is not the same thing as arguing that there should be no trials.

When we bend the rules in our favour, we cheapen our country. We become, in effect, the colonial power that the IRA accuse us of being, treating people living under our jurisdiction as something less than full citizens. Irish nationalism rests on precisely this claim. From the 1914 Curragh Mutiny to the 1974 Ulster Workers’ Council Strike, argue Irish Republicans, the British state has been prepared to bend the rules in a Unionist direction.

If we believe that Londonderry is a British city, then the people who died on Bloody Sunday were British subjects. If they were British subjects, then they – or their survivors – deserve the full measure of British justice. Without that principle, our Forces would be no better than the terrorist bombers they defeated. And that is not something we should ever allow.