EVEN when Scotland was prospering from the transatlantic plantation slave trade, strident voices in the Scottish Enlightenment railed against slavery.

James Beattie, who held the chair of Moral Philosophy at Aberdeen's Marischal College, wrote in 1790 that black slavery was "utterly repugnant to every principle of reason, religion, humanity and conscience".

But now it has been revealed large numbers of prominent Scottish slave-owners shared in £20 million compensation paid out by the British Government when Parliament passed the Slavery Abolition Act in 1833 – 26 years after the trade itself had been done away with.

The sum, which is equivalent to £2 billion today, was said to be equal to 40% of the government's entire budget.

Many thousands of pounds were given to Scots in compensation for slaves in the British Caribbean who had been emancipated.

The beneficiaries included Colonel John Gordon of Cluny, who in 1851 forced some 3000 of his tenants on the Outer Hebrides to emigrate to Canada. Cluny died in 1858, unmarried but with a number of illegitimate children.

A database, assembled over three years by researchers at University College London, indicates that Gordon received a total of £24,964 in compensation, relating to 1383 slaves across six plantations in Tobago, in the southern Caribbean.

Other Scots on the database, highlighted yesterday by prominent Scottish historian Professor Tom Devine, include James Cheyne, who cleared tenants from the Isle of Lismore in the 1840s and 1850s; the Malcolms of Poltalloch, who were involved in clearances in Argyll; Sir Archibald Alison, a noted social commentator; James McCall and Patrick Maxwell Stewart, who both had substantial holdings in railways; the Marquis of Breadalbane, and Sir William Forbes.

Mr Devine, director of the Scottish Centre for Diaspora Studies at Edinburgh University, told The Herald: "Although the database is hugely significant, it still doesn't reveal the full extent of the [slavery] connection [with Scotland].

"These are people on the list who were compensated for owning slaves but it does not include professional people, such as physicians, overseers, merchants and military people, who all gained from the plantation economies.

"The list is mainly, perhaps even exclusively, concerned with the Caribbean. The great Tobacco Trade of the 18th century in Glasgow could not have existed without un-free labour, though that has gone by the 1840s, which is the time of this database.

"However, one of the things that the database brings out quite clearly is the sheer treasure which many of these people gained."

Mr Devine added: "Glasgow is usually the place that is cited as having a colonial connection, but if you look at the range of names and locations on the database, it is everywhere in Scotland, particularly in rural areas. This is why some people have argued that these monies were very important in terms of such things as agricultural improvement and the like.

"Women [on the list] almost certainly had annuities based on the plantation profits of the period," he added. The extensive database lists 46,000 individuals who received compensation. Of these, 3000 had addresses in the UK – and some 20% of these had addresses in Scotland.

Professor Catherine Hall, the leader of the project and professor of modern British social and cultural history at UCL, said it was "very striking" how many slave-owners there were in Scotland.

She said: "The empire offered opportunities to the Scots on a very significant scale and working on the plantations was a favoured choice for Scots seeking their fortunes in the late 18th and early 19th century. One of the things we found is that far from the slave-owners all being concentrated in the great slaving ports of London, Liverpool, Glasgow and Bristol, there are people all over the country making claims of compensation."

Eric Graham, an honorary post doctoral research fellow at the Scottish Centre for Disapora Studies, said the compensation differed between the Caribbean islands. He said: "The figure was £6 for a child, an average of £50 for an able fieldworker, or between £18 and £20 if the fieldworker didn't have any specific skills to offer.

"For the top craftsmen within the slave population, like the sugar-boilers, who had a dangerous job and were particularly well sought-after, the figure might be £100.

"Slave-owners were allowed to claim compensation according to the composition of their workforce.

"A white artisan worker in Scotland would have been paid 25 shillings, of £1.25, a week, which is an instructive comparison."