But back in 1980 the concept of “reality television” was still a twinkle in the eye of television producers, even though prototypes existed in fly-on-the-wall documentaries like The Family (1974).

Alison Steadman believes this unfamiliarity with a genre which has now reached saturation point was one of the reasons that Enjoy, a play by the normally reliable Alan Bennett, flopped when it was first staged.

It is a comedy drama about an elderly couple from Leeds who are about to be moved from a decaying back-to-back into a modern maisonette, the transition being observed by a sociologist who sets up camp in their home.

“I think in 1980 people didn’t know what on earth was going on because it is kind of surreal,” says Alison, who plays Connie, generally referred to as mam, in the new production of Enjoy which arrives at Birmingham Rep next week.

“It is about people being observed and heritage, living museums where you go and watch how people used to live.

“Nowadays that is commonplace. Birmingham itself has got back-to-back houses you can go and look at. 

“And there are the TV reality programmes – people living like Victorians or like farmers in the 18th century. There are oceans of them, quite apart from Big Brother, so it is more of it’s time. 

“It is a very funny play but also very serious, quite sad in places.”

Mam and dad’s (David Troughton) discomfort with being watched by the silent stranger leads to her behaving in a manner of such exaggerated ordinariness, as she fusses about bringing out the best china, that gradually both of them start acting in ways that reveal themselves to be anything but a typical family.

“As far as mam is concerned she has got a visitor in the house and a woman of that type and at that time would take her apron off and try and be polite and chat,” says Alison.

“But because the sociologist doesn’t speak mam and dad start to say things they wouldn’t normally say and they suddenly realise they are behaving in a way that isn’t normal.”

Alison says the mam character is based partly on Bennett’s own mother.

“I think his own mother had dementia and mam is in the early stages. It is quite a difficult part to learn because she keeps forgetting things and repeating the same questions.

“The dad character has just recovered from a bad accident and is on tablets for anxiety. He is quite a bully and has ruled mam with a rod of iron and there is an anger in her about that.”

The play’s director, Christopher Luscombe, has cut it considerably – with Bennett’s permission.

“He has taken about half an hour out,” reveals Alison. “I thought Bennett would want to cut it himself but he said ‘No, get the scissors out and cut it’.

“Chris Luscombe is a very intelligent man and a tried and tested director, so it wasn’t a case of any Tom, Dick or Harry taking his play and tearing it apart.”

Newly trimmed, the production has met with full houses and a rapturous reception from the critics.

“I don’t read them in case I read anything bad and it upsets me, but apparently they were all excellent,” says Alison.

It has been such a success that the tour will conclude with a run in the West End, something that has delighted her, not least because  it means she will be able to go home to Highgate at night.

“I am a bit sick of touring to be honest. In a way it is nice it is nice to be in different paces but this play is very tiring. The young ones in the show are loving it because it is all new. When I was their age I was in rep for four years going all over the country doing seasons, living in digs God knows where. But I am 62. I don’t want to be ligging about the country really. I like to go home to my own bed.”

However, Alison admits she was so keen to play the part she agreed to do it even though she was committed to filming the Gavin and Stacey Christmas special.

“I didn’t want to miss it. The management gave me the time off but I had to come straight back and jump on the stage on the Monday which was quite difficult, not having done it for three weeks.”

The consequence of finishing filming in Cardiff at 10pm on Sunday and being in Chichester the following evening was a chest infection. However, Alison has trouped on. 

“It’s not possible to take a few days off,” she laughs. “I think you’d have to be hospitalised.”

Even after a 40-year career which has seen her come to rank alongside Julie Walters and Brenda Blethyn as recognised national treasures, Alison still has the compulsion that drives most actors never to turn work down in case the offers dry up.

“All actors love it if they are on a show they know is going to be a series because it is regular work and that doesn’t come along that often. It is getting harder and harder now and I feel very sorry for young actors. I wouldn’t recommend anybody to launch out on it. There are too many of us and not enough jobs.”

Since graduating from drama school back in the late 60s, Alison has managed to earn her living solely from acting and not had to fall back on the shorthand and typing her father insisted she learn in case she needed to support herself while “resting”.

“I left school at 16. My father persuaded me, quite rightly, to take a secretarial course because I could always get a job as a shorthand typist.”

She then worked as a secretary for the probation service in her native Liverpool.

At 19 she won a place at drama school.”

It was while she was studying drama that she serendipitously met Mike Leigh, the writer and director who became her husband. She starred in seven of his films and a number of his plays including Life is Sweet, Nuts in May, Topsy-Turvy and Secrets and Lies.

Although the couple, who have two sons, divorced in 2001 after nearly 30 years of marriage, Alison says they remain friendly and has not discounted the idea of a professional reunion. 

“Mike and I were a team. He employed me because he wanted me in his films and thought I was talented, not just because I was his wife.

“The work I did with him has been an essential part of my career. We  would be happy to work together.That is entirely up to him.”

It was Mike’s television play Abigail’s Party that launched her as an actress thanks to her riveting portrayal as the rhino-skinned hostess Beverly, a character so monstrous even Alison’s turn as the match-making Mrs Bennet in Pride and Prejudice did not manage to eclipse her.

“I don’t think you will ever bury Beverly, she wouldn’t stay down,” says Alison.

“The kids in the company, they are only 22, 23 and one of them came to me the other day and said ‘We had never seen Abigail’s Party and we got the DVD and we thought it was brilliant’.

“What actress is going to knock that for goodness sake? If you can do something that 30 years later people are still stopping you in the street and talking about I don’t think that is a bad thing. Unless I had never worked since then, then I would be really fed up.”

Enjoy is on at the Rep until Friday, November 15. For tickets ring 0121 236 4455.