FANS of the British Empire often point to its role in “civilising” foreign lands, bringing the benefits of tender governance to ignorant savages. Its supporters also point to Britain’s part in abolishing slavery.

Little mentioned is its role in promoting the African slave trade. Or its central part in narco trafficking in Asia. Both these atrocities were based on a golden triangle method. In the case of Africa, goods were shipped from London to West Africa, traded for people, who were then shipped en masse to the West Indies. There, these men, women and children were sold to be exploited in dreadful conditions to provide sugar. This sugar was carried in the now empty ships back to the UK for sale.

Huge fortunes were made from this trade. And royalty benefitted greatly. The Stuart kings and their predecessors and successors were major players in this evil business. The parliament in Westminster was deeply exercised by the slave trade. In the days of the major English player – the Royal African Company (RAC) – Parliament often debated freedom.

Not for the slaves, of course. Instead, there were furious debates about the freedom for others to breach the monopoly of the RAC, ­operating under royal charter. Many MPs were heavily involved in the slave trade, while others yearned to be part of it.

To ensure their properties were fully ­protected, English slaves were routinely branded RAC (Royal African Company) or DY (Duke of York), reflecting royal ownership.

READ MORE: BBC to investigate claims presenter paid teen for explicit photos

The slavery business of the English state ran for many centuries before reform gained any traction, and long before Scotland joined the Union. Over that time, the so-called ­Middle ­Passage gained a fearful reputation. As the name suggests, this was the second leg of the ­triangular trade between England, Africa and the West Indies.

The conditions aboard these ships were ­appalling with hundreds of slaves shackled in ­insanitary holds scarcely capable of holding their numbers. Slave ships, or slavers as they were known, could often be smelled before they were seen. Sharks followed slavers to feed on the bodies of unfortunate slaves thrown ­overboard.

One English slaver, Captain Phillips, ­complained that out of 700 Africans embarked on the Guinea coast, he could deliver only 372 alive in Barbados, where they sold for £19 per head.

Once landed in the West Indies, slaves often faced a worse fate. Indeed, the prevailing debate among their new plantation owners was this: was it cheaper to wear slaves out and buy fresh stock? Or to treat slaves with some humanity so they might last longer? The decision came down on the former. There were estates in Antigua where slaves seldom survived more than seven years.

Let’s turn now to what was the world’s ­major narco trafficker – the East India Company. Based in London, like the Royal African ­Company, its shareholders were drawn from the same “great and the good” of English, then ­British society. Many had shares in both ­companies.

This company also exploited a triangular trade. Goods were shipped from England to India, where opium was grown. This addictive drug was then shipped to China, sold for tea which was then transported to England.

READ MORE: Petition calls for Ruth Davidson to be removed from SRU board

When the Chinese emperor sought to protect his people who were being debauched in opium dens, the British acted brutishly. Two opium wars were fought to force the Chinese to free imports of opium.

One wonders how many Victorians supping their cup of Chinese tea in their china cup gave much, if any thought to the deplorable ­conditions inflicted on the poor of China.

Queen Victoria’s Indian subjects fared ­little better. And again, British force was used to ­suppress Indian objections. Indeed, the East India Company had its own private army of 260,000 soldiers, twice the size of the standing British army.

India has recently become the most populous ­country in the world. Britain must fervently hope that memories of past cruelty will lie lightly on the minds of those negotiating trade deals with the UK.

Think such attitudes to slavery are in the past? Here’s the secretary of State for Culture, Media and Sport, Lucy Frazer MP: “Oliver Cromwell defeated the Scots at Dunbar, incorporated Scotland into his protectorate and transported the Scots as slaves to the colonies.

“Now, there is an answer to the West Lothian question,” she crowed.

British schools implant notions of the ­greatness of Empire on scholars; but cover very little of the horrendous exploitation of many millions of ­innocent men, women and children to secure this “greatness”. It may help if the UK had fewer celebrations of worthies whose fortunes are based on “columns of blood”, and instead ­became contrite about the abuses inflicted by the Empire.

It’s not hard; last week the Dutch king ­apologised for his country’s part in the slave trade.

The TNT show returns on July 26