(CNN) — Grand buildings replete with turrets, picture windows and kitchen gardens. Perfectly manicured lawns. And hundreds of rooms stuffed with antiques and objet d'arts from across the globe.

Few things are as quintessentially English as a stately home. Tourists love them. And they're a guaranteed box office draw, as "Downton Abbey" and "Pride and Prejudice" can attest.

But there's a more disturbing side.

Many of these country estates are indelibly linked to brutal legacies of slavery and colonialism. And while their grim origins may have been previously overlooked, they're now facing a new level of scrutiny that -- amid raging debates over how Britain reckons with its imperial past -- has exploded into its own cultural conflict.

Published this month, the report identifies 93 places, roughly one third of all of its properties, that it says were built, benefited from or connected to the spoils of slavery and colonialism.

They include Chartwell, Winston Churchill's former home in the southeastern county of Kent, Devon's spectacular Lundy Island, where convicts were used as unpaid labor and Speke Hall, near Liverpool, whose owner, Richard Watt traded rum made by slaves and purchased a slave ship in 1793 that trafficked slaves from Africa to Jamaica.

Some 29 properties were found to have benefited from compensation after owning slaves was abolished in Great Britain in 1837, including Hare Hill in Cheshire, where the owners, the Hibbert family, received the equivalent of £7 million ($8.8 million) to make up for the loss of slaves.

"At a time when there's an enormous interest around colonialism more broadly and indeed slavery more specifically, it felt very appropriate, given that we care for so many of these places of historical interest, to commission a report that looks right across them and try to assess the extent of those colonial legacies still reflected in the places we look after today," says John Orna-Ornstein, the National Trust's director of culture and engagement.

Not everyone agrees. And in some cases the response has been one of indignation and fury.

'Shameful manifesto'

Lundy Island, a National Trust property in the Bristol Channel, where convicts were used as unpaid slave labor.

Alamy

When the National Trust first trailed its report and highlighted the connections on Twitter to mark UNESCO's Day for Remembrance of the Slave Trade and its Abolition, there was an inevitable backlash.

Replies to a Twitter thread that detailed how mahogany felled by enslaved Africans was used to build furniture for stately homes in the 18th century were swift in their disdain.

One complained, "Are you for real?" Others said they were canceling their National Trust membership in protest, saying the past couldn't be changed and that historical buildings were there to be enjoyed, no matter their past.

One said they did not want the National Trust to "ram it down our throats," while others talked darkly of "history being erased." Opinion pieces in newspapers decried supposed attempts by the Trust to somehow talk Br