In 1974, when Alan Ayckbourn wrote Absent Friends, Abigail Thaw’s father, John Thaw, best known as TV’s Inspector Morse, was just about to make the pilot for his other key role as tough talking detective Jack Regan in The Sweeney. Four years previously her mum, Sally Alexander, had found fame of another kind by flour-bombing the Miss World Contest at the Albert Hall. By that time, the couple had divorced and Abigail, who plays Diana in Watford Palace’s production of the play next week, was living with her mother in Pimlico. While women’s liberation and divorce were possible in real life, they were clearly unthinkable among Ayckbourn’s characters.

Inspired by a real life event, Absent Friends centres on a tea party organised by Diana to cheer up Colin, a friend of her husband Paul, whose fiancée has just died.

Plans go awry as no one knows what to say to Colin and John turns up with his wife Evelyn, who has been having an affair with Paul. Through it all, Colin remains perfectly happy while the others examine their less than perfect relationships.

Abigail sees the couples as being trapped by factors that do not affect us today.

She says: “There are two generations of women in the play, Evelyn is slightly younger and though she may be sexually liberated, she’s equally unhappy. She’s in a thankless marriage and is using sex to fill a gaping emptiness in her life.

“Looking at the older women, you can see why there was a feminist movement. They have all this intelligence and nowhere to direct it. That wasn’t true in my own case, as my mother divorced her husband, but most women weren’t educated to believe they had choices.”

Although Abigail sees Diana’s world as very different from her own, she can identify with her problems.

“In rehearsals, we've been referencing these old magazines like Cosmopolitan and the articles are mainly about how to have as many lovers as you want and adopting a throw your car keys in the bowl, not caring, attitude. It’s the rise of the sexually liberated woman after years of being held down.

“But, alongside all these overt articles egging women on about sexual freedom, there’s this advert for a savings account which says ‘Make him save properly’ and this was totally disempowering.

“Where’s the real power if you can’t take the bus into town, buy your own car or open your own bank account because you don’t have your own money?”

Many of these issues bubble under the surface in the play. Marriage in particular is seen as more of an institution.

“They were from an older generation and they just put up with it. They made it work in a way we don’t have to.”

Abigail and her partner Nigel Whitmey have two children, Molly Mae and Talia. They’re not married but have been together for more than 20 years. Abigail points out that although fewer people are getting married now, statistics show divorce rates are also in decline.

“Perhaps people are thinking more deeply about it now,” she says. “The 1970s was the advent of feminism but people just didn’t talk about things the way we do now. Women were under a stigma that said you don’t talk about sex or death.”

Death is ever present in the play and in 2002 Abigail’s father, died of throat cancer.

I ask her if it was more difficult to come to terms with what had happened while under the gaze of so many others.

“I was working at the time and I always thought the process was delayed for that reason. I was going to give up the project, but my stepmother said something to me about how he would have wanted me to carry on – he knew about the project and was very proud of the work I was doing. I went to New York and it was blissfully distracting. I wasn’t frightened, as I had friends and people I loved and trusted around me.

“Nigel lost his father when he was very young and he said to me when they made the documentary about my father, ‘how wonderful you have that and what a gift it is to our children to really see their grandfather’. It was good not to feel alone – the world should stand still because it’s so horrible and unfair, you think how can everything carry on, and because the world did stop in a small way it was a comfort.”

At this point Abigail is close to tears and I am too moved to speak. “I haven’t cried about it for months,” she says. “I was at a party last night for my stepmother’s new book and I guess that’s what brought it all to the surface.

“Richard Briers, who played Colin in the original performance of Absent Friends, was there. It was so lovely to bump into him and talk about it.

“I asked him what were his tips for doing Ayckbourn and he replied ‘I don’t know love, you’ve just got to play it real – it’s like Chekhov’. And he’s absolutely right. Ayckbourn writes about the human condition so beautifully.”

Absent Friends is at Watford Palace Theatre from Thursday, October 2 to Saturday, October 25 at 7.45pm with matinees Wednesdays at 2.30pm and Saturdays at 3pm. Tickets: 01923 225671 (£7.50-£21.50).