For connoisseurs of irony, tomorrow will be a busy day. In Berlin politicians will gather to toast the glories of Europe on the 50th birthday of the EU. Meanwhile in Britain the focus is on the 200th anniversary of Wilberforce’s great Act of Parliament that set in motion the abolition of slavery in the British Empire (though it took another 25 years for reality to match rhetoric). You don’t have to be a rabid Marxist to make a wry link between the two coinciding anniversaries. To a large extent — an extent yet to be fully acknowledged — Europe’s historic power, stupendous wealth and dazzling artistic achievements were based on its citizens’ remarkable talent for exploiting, enslaving and murdering the rest of humanity.

The evidence is all around us, though it is not often viewed as such. Those elegant Palladian mansions dotted around the English countryside, the superb Georgian terraces in London and Bristol, the grand palaces in Versailles, Vienna and Madrid, the priceless artefacts hoarded in the BM, the Louvre, the Uffizi, the Hermitage — a fair proportion of all these priceless cultural treasures, I would estimate, were bought or commissioned by men who became filthy rich through filthy treatment of their fellow human beings.

Yes, I know that slavery was never an evil inflicted exclusively by Europeans. It was (and still is) a moral aberration common to all eras and races. Tens of millions of Africans were sold into slavery by Arab traders and their own despots well before Europeans got the same idea. The United States, land of the free, enslaved a large minority of its own population until the 1860s, and effectively humiliated millions of black Americans for a century after that. Russia’s serfs, slaves in all but name, won their freedom only with the Revolution (and what a grim travesty of freedom that turned out to be). Indeed, you could argue, and many will do so this weekend, that Britain deserves not vilification for carrying human cargoes in indisputably horrendous conditions across the Atlantic for a relatively short period in its history, but praise for being the first tribal power in 50,000 years to renounce the illicit wealth that accrues from enslaving conquered populations.

Except that it would be grotesquely smug to argue in this way. We kid ourselves if we think that human nature has improved in 200 years, in Britain or anywhere else. And we compound the fallacy if we assume that by erecting cumbersome networks of social workers, national and international, we come any nearer to stamping out degradation. What we are doing is burying the problem in bureaucracy. In fact the Church Mission Society, the charity founded by Wilberforce himself to fight injustice, estimates that there are more people enslaved today than at any time in history: 20 million, compared with four million when the 1807 Act was passed.

What seems clear is that ostensibly “decent” people of all eras and nations have an almost limitless capacity for ignoring exploitative activities, if the abolition of those practices would significantly diminish their own power, wealth or pleasure. The most horrific example of that was the acquiescence of millions of ordinary Germans in the Holocaust. But to a greater or lesser degree every society finds it convenient to overlook activities that are morally wrong but economically or politically right.

That was certainly true in late 18th-century England. The overwhelming consensus was that the slave trade was theologically justified (the Church of England, to its shame, argued that a hierarchy of races was part of “God’s natural order”), historically inevitable (18th-century intellectuals revered the Classical civilisations of Greece and Rome, where slavery was rampant) and, most important of all, vital to Britain’s prosperity. As is vividly depicted in Hollywood’s latest costume drama, Amazing Grace, the hostility towards Wilberforce and his holier-than-thou “Clapham sect” was colossal, bitter, unremitting and personal — at every level. (The London church I attend has a particularly grisly record, since its vicar in the early 19th century, who held shares in the plantations, actually banned Wilberforce from attending services — even though Wilberforce lived in the parish. The great reformer retaliated by building a new church up the road.)

Yet Wilberforce, a backbench MP who eschewed normal political channels, “fixed the character of the times” (as his Westminster Abbey plaque puts it) to such an extent that a mighty empire voluntarily abolished one of its most lucrative streams of income. How did he do it? The answer is that he reawakened in millions the most mysterious force for good that human beings can muster — the still, small voice of conscience.

What an enigmatic and elusive thing a conscience is! In so many spheres it is entirely suppressed. Perhaps life would be unmanageable if it weren’t. Imagine giving a quid to every homeless person you passed, or sending a cheque to every charity whose begging letter came through your door, or checking every item in your shopping trolley against a list of multinationals who exploit African workers, or scrutinising your bank’s zillion-pound investments for hidden links to arms dealers. Even among saints, I suspect, conscience is a selective trait (though Wilberforce, who set up 69 charities, may have been an exception). In mere mortals it can lie dormant for years if it gets in the way of our pleasure.

“And what’s wrong with that?” you retort. “Life’s about enjoying yourself, not agonising over the human condition.” Well, perhaps. But it was precisely that thinking which led one civilised European population after another — the Spanish in the 16th century; the British in the 18th; the German and Russian in the 20th — to ignore atrocities committed in their name, and sometimes in their midst.

Through the power of his speeches, and through astonishingly modern media techniques that undermined Parliament by appealing directly to the public, Wilberforce stirred consciences across the land. When John Newton, the slave trader-turned-abolitionist, penned the line “I once was lost but now am found, was blind but now I see” in Amazing Grace, he found the words that would eventually speak for millions. Wilberforce opened blind eyes to the abject misery inflicted on distant multitudes so that Britain could enjoy cheap tobacco and sugar.

There are lessons here. We talk grandly of events that stir “the conscience of the nation”. But that’s a sloppy shorthand. Nations, corporations and supra-national monsters such as the EU and UN don’t have consciences. Only individuals do. And the world changes for the better only when enough individuals press for reform. It wasn’t governments that tore down the Berlin Wall, or demolished apartheid, or dismantled the British slave trade. It was the massed clamour of individuals whose consciences had been awoken — perhaps, like Newton, after years of moral blindness or Orwellian double-think.

So let’s return to the gathering grandees of the European Union, desperately casting around for a 50th-birthday “mission statement” more enthralling than “Together Since 1957”. It would be pleasant to imagine that they will commit our continent’s still vast wealth and influence to the final eradication of slavery, in whatever tragic 21st-century shape it manifests itself — whether the hideously tricked Chinese cockle-pickers drowned in Morecambe Bay, or the Albanian girls coerced into London’s brothels, or the 10p-an-hour exploitation of Far Eastern workers so that Westerners can cover their posteriors in nice jeans for ten quid.

The reality, however, is that the EU is a discriminatory club committed to doing what Europeans have always done best: looking after their own interests. Such organisations will never shake the status quo. How could they? They embody it. As always, it will be left to bold, articulate individuals to speak for conscience. We could do with a Wilberforce in Britain today — though I don’t think he would waste his time sitting in Parliament.

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