THE family of Victorian-era prime minister William Gladstone will travel to South America to apologise for the part their ancestor played in the slave trade, it was reported yesterday.

The Liberal Party hero — PM on four occasions in the 19th century — was the son of John Gladstone, one of the largest slave owners in the British West Indies.

Charlie Gladstone, the great-great-great grandson of John, said he “felt absolutely sick” when he found out about his family’s slave-owning past.

He and five other family members are set to travel to Guyana to apologise on behalf of their forebears, according to The Observer newspaper, which also said the family intends to pay reparations to fund further research into slavery’s impact.

John Gladstone was a Scottish merchant who made a fortune as a Demerara sugar-planter and had hundreds of enslaved people working in plantations in the decade before the 1833 Slavery Abolition Act. 

He received the largest compensation payment made by the slave compensation commission — around £93,000, the modern equivalent of about £10 million.

In 1831, William Gladstone used his first Commons speech to argue in favour of slave owner compensation, but in 1850, the ex-leader described slavery as “by far the foulest crime that taints the history of mankind.”

Charlie Gladstone told The Observer: “John Gladstone committed crimes against humanity — that is absolutely clear.

“He was a vile man. He was greedy and domineering. We have no excuses for him.”

The family plan to make their official apology at the opening of the University of Guyana’s International Institute for Migration and Diaspora Studies, which it is reportedly helping to fund with a grant of £100,000.