'I sit in front of the TV all the time, shouting'

Ricky Tomlinson – like Jim Royle, his best-known alter ego – enjoys a rant. He talks to James Rampton about prison, poetry, politicians, and his latest role, as everybody's favourite pub landlord

Wherever he goes, Ricky Tomlinson is chased by his catchphrase. The 73-year-old actor, best known as Jim, the crotchety dad from The Royle Family, takes up the story: "The other day, I did a charity Can't Cook, Won't Cook at a local golf club. On the way out, a posh woman came up to me in a mink stole, pink-rinsed hair and the obligatory pearls round her neck.

"She asked me, 'Will you please sign this photograph, "My bottom?"' I couldn't believe it! Did I write 'My bottom'? Did I, my arse! Of course I wrote, 'My arse!'"

Tomlinson, who is also an accomplished banjo player, says that whenever he goes out up to 50 people, from passing bus drivers to schoolchildren, will shout his catchphrase at him. "Do I mind?" he laughs. "Not in the slightest. I love it! The only time I might get fed up would be if people started asking, 'Who the bloody hell is that?'"

As you can see, Tomlinson has a likeable, down-to-earth attitude to showbiz. This, after all, is the man who takes cans of his favourite mild to awards ceremonies because he doesn't like Southern lager. He was also once introduced to Robert De Niro at the Groucho Club and, not having a clue who he was, asked him if he was in the business.

Despite the huge popularity he has enjoyed as Jim over the past 16 years, the actor is adamant fame has not changed him. He still lives close to where he grew up in Liverpool and is highly approachable. With him, he says, "What you see is what you get – warts and all." He has no desire to join "the luvvie set".

The actor, who lives with his wife, Rita Cumiskey, and has three grown-up children, is an irrepressible presence. He worked for many years on building sites and has long been a vociferous left-winger, only getting into acting after serving two years in jail. One of the so-called "Shrewsbury Two", he was imprisoned during the builders' strike in 1973 for "conspiracy to intimidate" on a picket line after he refused to testify against fellow strikers.

In jail, he discovered the joys of poetry and music. He also began to explore socialist theories, devouring a copy of The Ragged Trousered Philanthropists given to him by a sympathetic prison governor.

Soon after leaving, Tomlinson began playing his beloved banjo in pubs, before landing his first TV acting job in 1981 in Roland Joffé's Play for Today, United Kingdom.

A succession of high-profile parts followed, including the union activist Bobby Grant in Brookside and the irascible detective DCI Charlie Wise in Cracker. But it was the role of the impossibly lazy Jim Royle – whose stained stripy yellow T-shirt would run away in fright if it ever saw a washing machine – that catapulted Tomlinson to a new level in 1998.

He is a generous man – in 2008 he donated £1m to Alder Hey Children's Hospital in Liverpool. Tomlinson clearly adores working on Caroline Aherne and Craig Cash's long-running sitcom about a lovable, yet terminally indolent family apparently surgically attached to their three-piece suite.

And the audience love it just as much – the recent Christmas special netted 7.7 million viewers on Christmas night, beating Doctor Who, Downton Abbey and Call the Midwife.

Tomlinson says, "I'd love to do another Christmas special next year. In fact, I'd love to work on The Royle Family every single day. We're one big happy family. I'd do anything for Caroline. If she rang up and said, 'I've written a part for you, but you have to cut all your hair off', I'd be there in a shot."

So are there any similarities between the actor and his most famous alter ego? Tomlinson asserts he has a very different work ethic to Jim, the man who makes sloths look hyperactive. "His only job was when he was milk monitor at school. He's never got off his arse since. I'm totally the opposite. I'm from a family of grafters."

However, Tomlinson adds, "Like Jim, I do tend to moan at the telly. I'm always screaming at Prime Minister's Questions – 'Tell the truth!' Politicians are so skilled at not answering the question. They never give you a straight answer.

Tomlinson is now starring as Warren, the pub landlord in a new ITV1 drama, Great Night Out, which begins on Friday. The actor, who wrote a best-selling autobiography entitled Ricky in 2003, says that, "It's a really good comedy-drama about four couples who meet for a great night out every week in the local pub.

"I play the landlord who does everything in his power to keep people in the pub spending their ruddy money. He charges them for everything, even watching the football. He is a bloody know-all!"

Tomlinson will also soon be starring in BBC3's zombie drama In the Flesh. He is happy to be so busy. "I hope I never lose my passion. When I lose that, I'll be gone."