Classic BBC sitcom Steptoe and Son marked a turning point in British comedy in the early 1960s - a shift away from slapstick and farce to a brand of comedy entrenched in working class realism.
By Emma Saunders
BBC News entertainment reporter
The long-running show made stars of its leading actors Wilfred Brambell and Harry H Corbett, who played father and son rag-and-bone men Albert and Harold.
Isaacs played the troubled Harry H Corbett
But their on-screen sparring was mirrored off-screen in the pair's often fractious relationship.
Harry Potter star Jason Isaacs takes on the role of Corbett in a one-off BBC Four drama, The Curse of Steptoe, which examines how the sitcom's success came at a price for its two stars.
The script is based on interviews with those closely involved including writers Ray Galton and Alan Simpson and Corbett's first wife, actress Sheila Steafel.
Isaacs, who has also starred in Hollywood blockbusters like The Patriot opposite Mel Gibson and acclaimed TV series The State Within, describes the original Steptoe and Son as "a really groundbreaking piece of work" when it first started as a one-off comic play in 1962.
Steptoe actors Brambell and Corbett had a difficult relationship
Much of the drama focuses on Corbett's frustration at being typecast after he became known as Harold to millions of viewers tuning in week after week.
"I have friends who have been in long-running TV series... they're terribly popular but they feel like they've lost their way. And they often hate their job, they hate playing the person so beloved by the public," says Isaacs.
He describes Corbett, feted for his performances in Shakespeare's Richard II, as "Britain's Marlon Brando".
"He was a leading light of his generation, it was lost potential really."
Actress Sheila Steafel contributed to the show
Corbett is portrayed in the drama as a pompous, insecure womaniser but Isaacs has some sympathy for him.
"Harry is rounded. Part of what's interesting about telling stories on the little screen, is when you peel the layers back... everybody is human, everybody is frightened and everybody has emotional challenges, no matter how many things they've got or how many people love them."
Isaacs believes the sitcom and Corbett were victims of their own success.
"It (Steptoe) started out with such high hopes and it did entertain enormously for a long period of time but Corbett never got to spread his wings and do the things he was capable of," Isaacs says.
But the actor thinks a combination of luck and planning can help his fellow professionals avoid typecasting.
Isaacs and Davies were "nervous" of playing Steptoe and Son
"A lot of acting is to do with luck. The thing with typecasting - they can offer you the parts but you have to choose whether to accept them.
"Harry kept going back because he kept thinking, well, if I don't do it this year, what am I going to do?
"But I've deliberately kept moving the goalposts as much as possible," he says.
Given the subject matter, with the two men unable to escape each other and their personal problems, Isaacs is keen to point out how well he got on with Phil Davis, who plays Brambell.
"We got on fantastically well, we were both extremely nervous of the bits of Steptoe and Son that we had to do because every single person I mentioned it to went straight into doing an impression," he says.
Isaacs has one of those faces you will recognise but may not be able to place - considering his illustrious CV, that may be surprising, but he manages to keep a relatively low profile.
Isaacs spends much of his time working abroad
"I think in these days we're completely obsessed with celebrity - it's the new religion. One of the ways to be super famous is to court it, you have to want that," he says.
"I love my job and the variety but I've been lucky enough to know very famous people - their life is so compromised, there's no amount of money that's worth not being able to leave your front door.
But it just happens to some people - I worked with Orlando (Bloom) on Blackhawk Down, he could walk down the street, next time I saw him, he had a bodyguard. It didn't happen to me when I was younger and I am incredibly grateful that it didn't," he says.
Currently filming Paul Greengrass movie Green Zone in Morocco with his wife and two children in tow, Isaacs is keen to work in the UK next.
"I love my country, I love playing British people who I understand, but it's a job - I go wherever I have to."
The Curse of Steptoe can be seen on 19 March at 2100 GMT on BBC Four.