The motif of the "horrible family secret" is often found in American gothic literature. Think of Tennessee Williams’ plays. Unspeakable sins lie at the heart of many families he created. The very fact that their past cannot be spoken of only deepens psychological damage in the present. Donna Tartt’s The Secret History is a more up-to-date use of the theme: hidden crimes, and their destructive consequences.

Historically, it’s unsurprising America’s great writers tread this path. Their country is, evidently, built on terrible historic acts: the genocide of indigenous people, and the monstrous crime of slavery.

Yet British writers - and Scottish - seldom approach the past in the same way, either metaphorically or literally. Which is strange, given we’re just as steeped in slavery as America. In fact, America is arguably more advanced in confronting its past than European nations. America may be entirely dysfunctional on matters of race, but it cannot be said that it has failed to discuss historic crimes. The same isn’t true of Scotland, England, or many other European colonial powers built on slavery.

Read more: Professor Sir Geoff Palmer: ‘My family were owned as slaves by Scots. It’s time this nation faced up to its history

We hide behind our act of abolition, as if this washes our hands clean. Yes, Britain abolished slavery, but we were also key architects of the transatlantic slave trade. We helped invent the crime we later banned. Must it be repeated that Scotland was an active, eager participant in England’s acts of empire, colonisation and subjugation, including slavery?

If we expect the descendants of slaves to simply forget the past, we’re mistaken. For them, history isn’t secret or rarely spoken of, it’s fully present. The matter of slavery’s legacy won’t simply disappear. In fact, it intensifies.

Caribbean nations are preparing formal letters demanding the British royal family apologise and make reparations for slavery. The King’s direct descendants owned slaves. Justice demands a calling to account.

To the King's credit, he’s said he takes the issue of slavery “profoundly seriously”, calling it an “appalling atrocity”. However, he hasn’t yet formally apologised. Rishi Sunak has deliberately refused to apologise and blanked the notion of reparations.

The issue of apology is slightly muddied by the fact Tony Blair expressed his “deep sorrow” for slavery in 2007. However, at the time, former Labour MP Baroness King said: “The Prime Minister is stopping short of a full apology mainly because it leaves the state open to claims for reparations.”

Isn’t an apology due? Not just words of "sorrow", but an official recognition by the state that great crimes were committed? If that opens the door to reparations, well, so be it. That’s a separate discussion. Apology is good for the soul. This we know.

Yet many rage against the notion of apology. The standard attack line is "why should we apologise for something our ancestors did?". Gary Younge, one of Britain’s leading black writers, once told me he found it intriguing that the same people who trot out this line are often the first to say "we" won the war, when they weren’t alive in 1945. If we take credit for our ancestors’ heroism, then shouldn’t we also accept responsibility for their sins?

Read more: ‘Men with bats shouted the N-word’: Gary Younge on racism in Scotland

Another line is: "Well, the Italians don’t apologise for Roman slavery, or the Turkish don’t apologise for Ottoman slavery." However, there are no nations comprised entirely of the descendants of Roman or Ottoman slavery, as there are Caribbean nations today comprised of the descendants of European slavery. The victims of our ancestors are alive and before us. Many express great hurt at our failure to recognise the historic damage done.

We also live in a sociopathic age, where empathy is somehow sneered at. When Nicola Sturgeon, for instance, apologised for the murders of women - and some men - executed in Scotland as witches, it was described as "performative". The same was said when Ms Sturgeon apologised for cruel adoption practices, separating unmarried mothers from their children, in Scotland in the past.

The word "performative" seems to be applied to acts of kindness or humanity which some simply despise for their own, perhaps rather unpleasant, reasons.

Should Britain not have apologised for failing to do more during the Irish famine, as happened in 1997? Did shell-shocked soldiers who were "shot at dawn" in the First World War not deserve their apology?

Much apology is already happening. The Church of Scotland will apologise for its links to slavery. Both Edinburgh and Glasgow councils have apologised for historic connections to slavery. Glasgow University promised £20 million in reparations, for educational research in the Caribbean related to slavery, after uncovering its own ugly historic past. The Dutch and Danish governments have apologised. The SNP has pondered the issue of an official apology from the Scottish Government.

There’s now a small band of folk whose families got rich from slavery now trying to make amends for what their ancestors did. Among them is the writer Alex Renton. He’s written of his family’s ancestral involvement in slavery, and launched the lobby group Heirs of Slavery, which backs calls for apology. As he points out, when Britain abolished slavery, families like his were richly compensated for "giving up their slaves".

“That huge injection of cash seeded new fortunes,” he says. Some descendants have already started paying reparations. The family of BBC journalist Laura Trevelyan gave £100,000 to the University of the West Indies, and apologised in Grenada for ancestral ownership of 1,000 slaves.

Read more: How Scots were foot soldiers in England's colonisation of Ireland

Other families are different. Former Tory MP Antoinette Sandbach wants to be removed from research which connects her to a slave-owning ancestor.

Judge Patrick Robinson, of the international court of justice, who presided over Slobodan Milosevic’s trial, says Britain can no longer ignore calls demanding reparations for the “greatest atrocity”. The descendants of former British Prime Minister William Gladstone have apologised for their family’s involvement in slavery and urged the Government to discuss reparations.

This terrible sin, and the wound it leaves in our national soul, must be addressed. Apology is a start. If the UK Government won’t do the decent thing, then there’s no reason why the Scottish Government cannot move unilaterally issuing a formal apology. Once that simple act of decency is completed - once we’ve faced our "horrible family secret", our little spoken of historic sins - we can then turn to the issue of reparations.