You can almost feel the slavery reparations debate drifting balefully towards Belfast, not that slavery will be the issue once it touches our shores. It is impossible for historic British wrongs to be discussed anywhere without somebody making a reference to Ireland, which is then picked up and picked over by both sides in Northern Ireland.

Irish businessman Denis O’Brien has been a prominent lobbyist for slavery reparations to the Caribbean, although he has not made comparisons with Ireland or singled Britain out from other colonial powers. Spurious comparisons between British rule in Ireland and the Atlantic slave trade found a nexus beyond parody last year, when former BBC journalist Laura Trevelyan said her family would consider reparations for the Great Famine, having just donated £100,000 for owning slaves in Grenada.

The growing fashion to see the world in postcolonial terms has proved irresistible to a certain kind of Irish exceptionalism. Reparations add the prospect of cash to the moral superiority of victimhood. This is destined to be a popular mode of political thought.

Academics have been using the term “reparations” in Northern Ireland to refer to what most people call Troubles compensation schemes, such as the pension for the permanently injured, opened to applicants in 2021. This painstaking work should be distinguished from unrelated arguments about slavery – the concept of Troubles reparations can be divisive enough.

However, there are people who are committed to connecting every sin of the imperial past to Northern Ireland’s present, in a grand unifying theory of British evil. They will elbow their way into any discussion on reparations and make it about them, creating yet another argument about them and us. Debate on a united Ireland will be the first casualty. Republicans have spent a decade deflecting from the cost of unification by insisting Britain will help to pay for it. Absurd claims about London continuing to fund state pensions or deliberately concealing tax revenues at least pretend to be grounded in technicalities, but they slip too easily into a general sense of historic.

In April, an economic study put the cost of a united Ireland at €400 billion over 20 years. Asked about this by Newstalk, former Sinn Féin general secretary Robbie Smyth said: “I think there’s an issue about British reparations because that’s what it should be; it’s the outcome of their colonialism on the island. They should pay and they should be glad to pay.”

This view fires republicans up with resentment and antagonises unionists with an attack on their country. It is hardly conducive to reconciliation but it is great for venting an ancient grudge, which often seems to be the point. The worst damage postcolonial rhetoric does to Northern Ireland is to chip away at the foundations of the peace process.

Sinn Féin entered that process in 1987 with a document demanding “decolonisation” under United Nations principles. It quickly dropped this language and eventually accepted an agreement that addressed Northern Ireland as a modern European sovereignty dispute. The peace process was de-decolonised with good reason: it avoided any conception of the unionist population as settlers, with implications even republicans baulked at once they had to confront them. Backsliding on this through intellectual laziness is inexcusable. It is a pity unionists will not defend John Hume’s vision of Northern Ireland as a European problem, if only to provide some post-Brexit comic relief.

American liberal politics has driven interest in slavery reparations across the world. This influence has a counterpart in the American myth of “Irish slaves” – the claim that Irish indentured servants in Britain’s colonies suffered similarly to African chattel slaves. The myth is used to denigrate African-American history and elevate Irish victimhood. Further arguing over slavery could cause a bizarre transatlantic cocktail of racism and antiracism to poison Irish politics from left to right.

Watching all this with clear exasperation are the people of Britain, upon whom any bills would fall. There appears to be some public willingness to consider modest reparation proposals, such as apologies and better-focused development funding. But there is also incredulity at the vast sums some are demanding and suspicion over the British government’s urbane waffling around the issue at last week’s Commonwealth summit. Labour prime minister Keir Starmer is not trusted to defend British interests.

Robert Jenrick, one of two candidates for the Conservative leadership, has tested out a robust response to the reparations debate. “I’m not ashamed of our history”, he wrote in the Daily Mail. “Many of our former colonies – amid the complex realities of empire – owe us a debt of gratitude for the inheritance we left them.” British politics many not be heading quite that far into a Trump-type future, but patience with grandiose demands and grievances will wear out. Then everyone will be back to where we are now, only a little bit angrier than before.