"Do you ever feel," I ask Felicity Kendal, "a bit like Kim Cattrall, who played Samantha in Sex and the City?" To compare Kendal – lovely, lovely Felicity Kendal, still the nation's sweetheart 30 years after appearing as the doe-eyed, dungaree-clad Barbara in the BBC sitcom The Good Life – with an American actress best known for her role as an oversexed, foul-mouthed New York glamazon might be considered incongruous, heretical even. But both belong to that category of actors and actresses who inhabit a certain role so convincingly, that they will forever be confused with that character.
Cattrall, evidently frustrated by this almost wilful blurring of fantasy and reality, once tried to clarify that, "the good news is I'm not Samantha... and the bad news is I'm not Samantha". If it irritates Kendal, however, she's not letting on: "It would annoy me if The Good Life wasn't showing any more," she says in that distinctive voice, midway between a gurgle and a growl, at once terribly well-spoken and lasciviously cracked. "But it's always on some channel or another. I think it's rather nice. It's following me like a good fairy."
Her cheeriness is impressive, all the more so if it is merely the polite façade of a pro. When we meet at a hotel not far from her Chelsea home, it's to talk about her forthcoming appearance in the title role of Mrs Warren's Profession, transferring to the West End after a successful regional tour. Since The Good Life, Kendal has built up a satisfying body of theatre work, tackling meaty roles and weighty subject matter in works by Beckett, Chekhov and Shakespeare, and scooping up several awards in the process. And yet, here she is again, answering questions – mea culpa – about Barbara.
I suspect, however, that Kendal, now 63, is astute enough to know that the coagulation of on- and off-screen persona has been more of a blessing than a curse in her case. "She wasn't a fantasy figure exactly," she says of her Good Life character. "But she was the one that wasn't entirely real. The others were the sort of people that everybody knew. She had all the ingredients – feisty, strong but adoring, up for anything, very funny – that people find attractive. It was a good creation that sort of grew and grew. I saw a clip of it the other day and that is so not me that I think, now, from a distance, that was really good acting."
It certainly convinced the generation of men who saw the series first time round, and those who have seen the subsequent re-runs. When I mention I am interviewing Kendal, it provokes a more enthusiastic response than any perky young popstrel has ever elicited. Twentysomething males tell me she is their ideal woman. One man makes me aware of the existence of a clutch of Facebook groups dedicated to the actress and her famously award-winning posterior (Rear of the Year, 1981).
The widespread slavering is almost frighteningly uniform, in fact, and it's easy to see why more ardent feminists at the time might have considered the Barbara character an unhelpful sop to male fantasies and Kendal, by extension, a treacherous conspirator in it all. Now, as Mrs Warren, she is clashing with the feminists once again, although this time it is the blue-stockinged variety of the late 19th century.
In Shaw's play, initially censored for taking prostitution – the unnameable "profession" of the title – as its subject matter, Kendal's character is rejected by her daughter when the young woman discovers that her comfortable lifestyle and expensive, Oxbridge education has been funded by a string of brothels managed by her mother.
"What Shaw is trying to do," explains Kendal "is to open up this incongruence in a society where women were supposed to be so respected and respectable that, if they took up a life of ill repute in order to improve their lot, which was pretty ghastly for most of them, it was alright as long as nobody talked about it.
"The question is, is respectability worth anything? Is it better to basically be a slave to your situation and die respectable, or, if you have no education and a gift for entertaining people in whatever way, to choose to do something that others consider unacceptable? Mrs Warren is able to give her daughter an education – she creates a modern woman and the modern woman then judges her. Would it have been better that her daughter, too, became a slave and died in the poorhouse?"
The extent to which the themes of Shaw's play are topical, more than a century later, borders on the laughable. Kendal arrives at our interview fresh from promoting the production on a London TV news programme. In the same way that Shaw was forced to refer obliquely to prostitution in the play's title, Kendal was asked not to mention the "p" word since the programme would be airing early in the evening.
"It's so in the news, it's a joke," she reflects. "There's one rule of how you are supposed to live and then there's the other situation which is reality. And we are constantly shocked by reality. Well, read a book, get a life. It's total hypocrisy, and it's something that we don't seem to have moved on from. Women are not, thank god, in that same position – or, at least, not in their hundreds of thousands – but we still judge in the same way."
Does she find it depressing that we have, in some respects, put such a paltry distance between ourselves and the society in which Shaw was writing?
"It's not depressing as an actor because what you learn in the theatre is that the classics are the classics because human nature does not change. The emotions are the same – love, loss, jealousy, greed. We haven't invented a new emotion.
"But what we don't have a lot of these days is the acceptance. It's all 'Look – baddy! Baddy broke the rules!' My question is, maybe we have to change the rules, because at the moment it doesn't seem like there are enough people able not to break the rules. And if people think that it's only the wealthy or famous, I really think we have no hope. There's something that this play attends to which is a biological mismatch between what we think people should be like and what they actually are."
Kendal herself is no stranger to what others might consider transgression of the rules. Twice married and twice divorced, her second marriage came to an end when she began a relationship with the playwright Tom Stoppard, who in turn left his wife Miriam for Kendal. A decade later, not long after separating from Stoppard, she and husband number two, the theatre director Michael Rudman, reunited. Kendal rules out marriage ("I'd feel like a bit of a tit, I think"), but the couple have been back together for more than a decade now and it's Rudman who is directing Kendal in Mrs Warren's Profession. She is relaxed on the subject.
"We had a very good divorce – so good, in fact, that it didn't take. The friendship and the understanding didn't change, and I think that is probably luck, but as divorce is more common we'll get better at it. You can grow apart at different stages and sometimes the reasons make it impossible to stay close, but if you can stay close and acknowledge that you've had a life together, you can think 'oh, we've sorted that bit now'."
For another actress, her media spell as "the other woman" might have been enough to wreck her public approval ratings, and it's here that the ghost of Barbara may really have acted as the "good fairy" to which Kendal refers. "I think people are quite fair," she muses. "If your body of work represents you, I think people, unless you have committed murder, take everything else into account."
In a similar manner, perhaps also because of her good theatre work, the public has been willing to overlook some less successful television efforts over the years; series such as Honey for Tea, The Mistress and the murder mystery Rosemary & Thyme have produced patchy results. Perhaps there simply aren't as many good parts for actresses – and particularly older actresses – on television as on the stage?
"It's all in the writing. I'm asked to do quite a lot, but they're not what I want to do. I think the roles are there in TV though. As we go on, I think there will be more women writing and more of us will be in positions of power for writers to write about," says Kendal, who confesses that she favours American sitcoms such as Two and a Half Men and Friends over current British television.
Nor does she have much time for complaints of ageism: "There is ageism, but that's quite right – it happens with men, too. You don't want an 80-year-old man reading you the news, I don't think. It just happens with women a little bit earlier, because women are supposed to look so good, and that's what we go out and spend our money on, so it's our fault, too. So when we stop looking so good then people start to get a little nervous. But I think it's much less of a problem now.
"The people who do make a difference – writers, politicians – their looks might be noticed, but it's not their value. You mustn't get confused between people who really need to look good for the job they do and women as a whole. If all you are selling is how you look, eventually you're going to get less money."
There are plenty of women out there who would disagree with Kendal's world view, but you get the sense that she has been so good at negotiating, and even beating, the system, that she might find it impossible to conceive of how others could feel hard done by. How many other women manage to pick up their CBE in the same year that they are voted, at 49, one of FHM's 100 sexiest women? If she's not exactly a woman's woman, she's not a man's woman either. If Kendal is anything, in fact, she is simply her own woman.
'Mrs Warren's Profession' will be at the Comedy Theatre, London, from 16 March. Booking to 19 June (0870 060 6622; ambassadortickets.com)
Her good life...
1946 Born in Olton, Warwickshire, to actor parents.
1965 Stars in Shakespeare Wallah, a film based on her family's experience as touring actors in India.
1967 Makes her London stage debut in Minor Murder.
1968 Marries Drewe Henley. They divorce in 1979.
1975 Appears in The Good Life . It runs until 1978.
1980 Plays Viola in the acclaimed BBC production of Twelfth Night.
1982 Stars in Tom Stoppard's The Real Thing. They form close relationship.
1983 Marries Michael Rudman, and converts to Judaism.
1990 Kendal and Rudman divorce following Kendal's affair with Stoppard. Kendal later reunites with Rudman.
1995 Awarded CBE.
1998 Publishes memoirs, White Cargo.
2003 Plays Winnie in Samuel Beckett's Happy Days. Stars in the TV drama Rosemary & Thyme, which runs until 2007.
2008 Appears in Doctor Who episode, "The Unicorn and the Wasp".