Disney Plus has added a content warning to the beginning of 18 episodes of The Muppet Show, the BBC reports.

"This programme includes negative depictions and/or mistreatment of people or cultures," it reads.

"These stereotypes were wrong then and are wrong now."

The disclaimer has been added to each of the episodes for different reasons, including one where Johnny Cash sings in front of the Confederate flag.

The Confederacy was the group of southern states that fought to keep slavery during the US Civil War and the flag is seen as a symbol of racism by many.

Disney's disclaimer added: "Rather than remove this content, we want to acknowledge its harmful impact, learn from it and spark conversation to create a more inclusive future together."

The re-assessment of old content was prompted by the Black Lives Matter protests last summer, and has sparked debate around programmes and films ranging from Fawlty Towers and Gone With The Wind to Little Britain and Bo' Selecta.

The 18 episodes of The Muppet Show with the warning have been picked out from five series of Jim Henson's series, which was a big hit in the 1970s and 1980s and starred Kermit the Frog and Miss Piggy.