After growing up in south West London, Planer studied acting at the London Academy of Music and Dramatic Art before embarking on a career in comedy.
His most famous role was Neil in The Young Ones, which ran from 1982 to 1984, but he also appeared in Blackadder, The Bill, and Death in Paradise.
Asked if he ever suspected that his father was Jewish while growing up, Planer said: “It was probably always in the air, but when you’re young you pick up a vibe, don’t you?
“It was so strongly inculcated in me not to ask, not to say anything. Don’t put your neck out, don’t sign anything, definitely never join a political party.
“I remember things like when we’d go to a restaurant he’d say, ‘Check the flowers for microphones’ — he probably got that from his relatives who had gone to Romania. When you’re told that as a kid, it makes a big impression.”
He and his brothers, Geoffrey and Roger - he told the Sunday Times - have tried to unpick the secrets of their father's life.
“We’ve got papers from Berlin, documents giving my granddad permission to enter Britain, papers showing them trying to get to Brazil,” he said.
“More papers than I can read, really.”
Tom Stoppard’s play depicting a Viennese Jewish family, Leopoldstadt, captured his relatives well, he said.
“That kind of hits the culture of my family. Not religious, lots of scientists, lots of them marrying out.”
Despite his father’s eventual admission of his Jewish background, he said, he does not consider himself Jewish.
“I think of myself as a category error, a misfit,” he said. “I don’t want people to put a label on me.”
George’s death, aged 96, in 2016 was lucky in a sense, he added, because it meant he missed Brexit, the election of Donald Trump and Jeremy Corbyn.
“The savagery of the communists was given no greater respect in my family than the savagery of the Nazis,” he said.
“We’re not Cambridge communists, those poncey English bastards who think Russia good, Germany bad.
“Then we were given a choice between Corbyn and Johnson, and that was the sh****est choice of my lifetime, and I’m 70.”
