This may be controversial but I want to deepen my understanding of slavery on the west. I ask because there is alot of talk that white people were slavers etc. Which obviously they were (as a culture), but what about your regular working man? I can imagine a slave would have been something he could not had afforded even if he wanted.
The short answer is, for 'your regular working man': virtually none.
If you were a wealthy aristocrat, then you may or may not have owned household slaves.
But British slavery was mostly a colonial institution, which grew out of the Caribbean sugar plantations.
To get a bit more complex: chattel slavery in England (which had been common in Roman and Anglo-Saxon times) faded out as a large-scale institution following the Norman conquest in 1066. The church vocally opposed the enslavement of Christians, and William the Conqueror brought the Frankish prohibition on slavery with him when he established the kingdom.
And everyone lived happily ever after.
Reality, as ever, is more hazy. Britain continued to have a very long tradition of forced labour, ranging from the serfs of medieval times (who owed lifelong service to whomever happened to own the land they lived on), through the indentured servants of the colonial period (essentially limited-term debt slavery), and ending in Victorian-era workhouses (a.k.a. 'prisons for the poor', outlawed in 1930).
Although they often lived and worked in appalling conditions and could not leave, the people trapped in these systems were not technically the property of anyone else and fall outside the umbrella of chattel slavery. This may seem like splitting hairs, but was important at the time - holding fellow Christians in slavery was shunned, but holding fellow Christians in serfdom was the bedrock of the medieval economy.
Anyway, the point here is that the underclasses of desperate poor meant that Britain never had any real need to import foreign slaves en masse.
Britain went on to become a major participant of the Atlantic slave trade, especially as the labour demands of the colonial plantations grew beyond the available pool of convicts and indentured servants.
Although the vast majority of slaves were shipped to the plantations, some were also sold in British ports, mainly as household servants to aristocratic families, not unlike the domestic slaves in the American South.
Slavery remained a contentious topic throughout the colonial period, as British law contained no provision regarding it one way or the other. This essentially left the courts to veer between pro- and anti-slavery stances at the whim of individual judges.
As early as 1569, the courts informed an abusive English slaveowner that 'England was too pure an air for slaves to breathe in' and that 'no Gentleman was to be whipt for any offence whatsoever'. The slave in question was Russian and almost certainly Christian - as in the medieval period, faith is a recurring theme, which would at first go on to work in favour of African slavery, and later become an argument against it as the slaves increasingly Christianised.
A 1705 case concluded that 'no man can have a property in another' and 'as soon as a negro comes to England he is free'.
However, a 1729 ruling determined that 'a slave coming... to Great-Britain or Ireland... doth not become free' and 'his master may legally compel him to return again to the plantations'.
But a 1763 case granted a slave freedom and a considerable inheritance after the death of his unmarried master, rather than allowing him to be inherited as property by his master's uncle.
Then a landmark 1772 ruling by the King's Bench (High Court) overturned the earlier 1729 decision and established that slavery was not protected by the law.
Slave trading (but not ownership) was banned in 1807, criminalised in 1811, and made into a capital offence after 1827. The Royal Navy began to aggressively hunt slave ships, (first only British, and later foreign-flagged) and levied heavy fines on those they caught, now equal to ~US$8,000 per slave onboard. Britain began to pressure other European powers to end their own slave trades, and finally outlawed slavery in 1833.
And everyone lived happily ever after.
Yeah. Unfortunately this centuries-long flurry of back-and-forth public opinion and legal wrangling, was focussed on the status of slavery within the British Isles, which had never been a major destination for Britain's slaves to begin with.
By the mid-18th-century, London was home to the largest African population in the UK: approximately 10,000 slaves and freemen. Although substantial, this comprised ~2% of the city's population. Meanwhile the American colonies were ~20% African (mostly enslaved).
The ugly truth is that colonial slavery was immensely profitable for Britain, and despite some grassroots opposition at home, the government appears to have been fairly happy to turn a blind eye to the rest of the empire.
They operated slave plantations in Jamaica even as they sent an army to fight alongside the slave revolt against France in Haiti.
The 1833 ban exempted the East India Company, leaving millions of Indians enslaved under British masters for another 28 years.
British industry continued to rely heavily on cotton from the US South and, until the Emancipation Proclamation added a moral element to the fighting, even considered intervening in the American Civil War on behalf of the Confederacy.
Across the centuries of Empire, Britain's official attitude toward slavery appears to have boiled down to 'Not in My Backyard'.
So, to answer your original question: very few common Britons would have owned slaves, or even known somebody who did.
But I feel it's important to emphasise that racism is not necessarily measured in shackles.
Attitudes in Britain were largely in line with their time. Although equal under the law, free blacks in Britain faced discrimination. 'Scientific' racism was not only widespread at the time, it was taken seriously enough to influence international policy (military recruitment in India, support for Imperial Japan, the partition of China...)
Some of the more charitable theories of the day proposed that black Africans were... built for brawn over brains. Others went to far as to posit that blackness was a hereditary disease, or that Africans occupied a lower rung on the evolutionary ladder.
The extent of racial friction in the UK was (and so some extent still is) buffered by class consciousness. Some African freemen did manage to flourish and join the upper class, and once there would have at least been considered superior to the lower classes.
But the government never made any serious attempt to provide assistance to the slaves it freed (in contrast to their former masters, who received sizeable payouts).
Without assets or professional training, and in a society where many believed them to be naturally deficient, many fell into the lower class.
And to bring things back around, the lower class was not a good place to be in premodern Britain. Out of the frying pan and into the fire...