Sybil was the wife of John Cleese’s Basil Fawlty, in the show’s two series made in 1975 and 1979.

Set in a dysfunctional hotel in the seaside resort of Torquay, it became one of Britain’s best-known comedies and was shown around the world.

It continues to be broadcast and referenced in popular culture now.

“Our darling mother Prunella Scales died peacefully at home in London yesterday,” her two sons said in a statement.

“She was watching Fawlty Towers the day before she died.”

Scales was married to actor Timothy West for 61 years. He died last November. She had been suffering from dementia.

Fawlty Towers was named as the greatest ever British TV sitcom by the Radio Times magazine in 2019.

It was developed into a theatre production in Australia in 2016, and it moved to London’s West End in 2024.

In the show, Sybil was often on the phone saying “Ooooh I knoooow”, her braying laugh described by Basil’s character as akin to “someone machine-gunning a seal”.

Her seven-decade acting career included multiple roles from the 1950s, including in 1960s sitcom Marriage Lines.

She starred in the 1992 Oscar-winning film Howards End alongside her son, the actor Samuel West.

In the 2010s, Scales and her husband travelled on their narrowboat in the Great Canal Journeys TV series.

She was born in Surrey in 1932 and started her acting career at The Old Vic Theatre School in Bristol.