Very few people are known the length of the country by their first name, though many would like to be. Di probably edges Cilla into second place, though not by much. And Cilla knocks all the Richards and Judys, Annes and Nicks, Vanessas and Esthers into a cocked hat when it comes to instant recognition. Which is the way she likes it. Indeed, she thrives on being spotted. "It annoys me when these upstart five-minute wonders say `Oh, I can't bear it. I can't go anywhere'. If you can't stand the heat, get out of the kitchen. It goes with the job. In fact, I'd be very upset if you didn't recognise me."

No danger of that. Cilla in the flesh is just like Cilla on the telly. She is resplendent in lime green top and shoes under a navy suit with enough gold trimmings to set off a metal detector, even today when she hasn't been in the studio. She complains about having had to do her own hurrr today, but it looks like it always does - she's been dyeing it that flame colour since her early teens. What with the orange flash of hurrr, the solid pink cheeks, the substantial teeth, the wide smile, the way she leans over occasionally as if to pat a nearby knee reassuringly, she illuminates the drab interview room at LWT's offices. It's hard not to believe that at any moment she will announce that there is a bevy of nervous young men lurking nearby, awaiting a thorough Blind Date-style grilling.

The 12th series kicks off next Saturday; but anyone who has lived in a cave for the last decade or so may still require some explanation. A stooge, male or female, has to select a date from a hand-picked selection of three hidden behind a screen, who attempt to impress with their witty repartee. Lame and, if possible, highly suggestive puns are generally preferred, though Cilla says that viewer complaints are far more likely to be about her outfits than any smutty jokes. The couple are then sent on a "date" which, far from being your standard couple of drinks in the pub followed by a stuffed-crust special at Pizza Hut, is likely to be a trip abroad. The following week they report back. Did they fancy each other? Did they hate each other? Might they (gasp! giggle!) have kissed, or even more?

For the past 11 years, the nation has held its breath to know the answers. Blind Date pulls in as many as 12.5 million viewers each week. Why, why, why? The answer, of course, has to be Cilla; though she denies it. "It would be terribly easy for me to go out and do an act, 'cos I'm in showbusiness," she says modestly. "But with Blind Date, I have eight people every night: I have to promote them to make the show work."

Oh, come on, Cilla! As if those mouthy, gauche little contestants could do it without you! And the suggestion that Blind Date is the vehicle that has propelled her to her current heights of the superstar stratosphere is countered with a distinct steely flash - "I'd like to think I had a hand in that as well" - tempered with a laugh.

Her humble origins are well-documented. Her father was a docker, and the family lived over a Liverpool laundry. As a child, she sounds as though she was a precocious little show-off. "I was performing on the kitchen table in the front room in our house when I was about three years old, and when I got that first round of applause from relatives and friends, I was just hooked. I started singing in Liverpool in and around the clubs and the same thing happened."

It's hard to believe, looking at jolly Cilla today, that this universal auntie was ever cool. But, with the Beatles, she was a product of the Cavern Club, epitome of the fresh new Sixties sound. She had her first No 1 hit at 18. "I became a big pop star overnight," she says casually, as if it might happen to anyone, just like that.

And she was already developing the larger-than-life Cilla personality. "I did shows like Jukebox Jury, and they said `This one can speak and she can be quite funny at times - she should be on TV.' Just to go on TV and talk to people, well, it was the easiest thing in the world for me. So then I had two careers because not only was I on the telly, I could still fill theatres and sell records - big hits."

So what stopped her being another Dusty Springfield or Marianne Faithfull? The lure of domesticity, because this was all back in the dark ages when glam careers and kiddies didn't mix. She married former baker's boy Bobby Willis, who she met when she was 16, and he now runs her business affairs (and sits in on interviews, joining in occasionally, as a genial-Scouse foil. They are like a practised and affectionate double act, and after three decades plus of marriage it is probably no act). "At 25, I thought `God, I've been a pop singer for six years' - it was quite a long time and I wanted to have children, desperately. All my girlfriends had two kids and I always wanted about six kids, so I thought, well, I'd better do something about it. All those years ago, if you got married or had children, that was the end of your career as a pop singer and I said `Well, to hell with this! I'm going to get married and I'm going to have children!' " Though, oddly enough, the babies that knocked her pop career on the head, did wonders for her status on television. "When I had our Robert, who's 26 now, the career just went from strength to strength, because they said, `Hey, God, she can sing and she can actually have kids as well, she's dead normal!' " She eventually totalled up three sons; a handy bunch, as Robert and Ben both help out in the Cilla Black empire, while Jack is still at private school.

Nowadays, she is patient with youngsters who don't remember the times when she was the Kylie of her day, even sends herself up a bit. "The 18- year-olds on Blind Date, they weren't born, so I had to make a kind of joke of it really, because they look at me and they think `God, Cilla who does Blind Date and acts a bit daft - a pop singer?'"

She maintains the famous accent, even though she has long since quit Liverpool for a large house in the exclusive surrounds of Denham in Buckinghamshire, and has now lived longer in the south than the north; though she says aggrievedly: "I don't really have a thick Liverpool accent - you watch Brookside! I have tried not exactly to lose my accent, but to try to talk a bit posher and I think I've done a good job, don't you, Bobby?"

Sadly, posh talk has not been enough to win over some of the neighbours. When Cilla and Bobby recently wanted to extend their garden pond (they say) or excavate a small lake (according to local planning permission enthusiasts), locals rushed to the tabloids to complain about their stand- offish attitude, quite unlike the charming demeanour of other village celebs such as, erm, "Paul Daniels and Patrick Mower," as cited by one lady councillor in a frenzy of name-dropping.

"There's a couple of them that have been like that ever since we moved in 25 years ago," says Cilla. "We were pop singers then, they told us to get back to where we come from, stuff like that. They're no bother - they're seven acres away from the house. I don't hit back because I wouldn't know them if I fell over them," she adds serenely.

Let them eat their words, anyway. These days when she goes home to visit, it's a far cry from the days 30 years ago when she'd drive all the way home from London for Sunday lunch because she was homesick.

"I go up all the time - only now, we hire a plane. That sounds dead posh, but to get to Liverpool now we have to fly into Manchester and then it's another hour's drive. Now I live down the road from a little airfield, so we hire a little plane and get in there, and its only 12 minutes to visit my mum."

There's really no need to explain: virtually anyone, given the choice, would take the plane rather than the train. But, at the same time, she hastens to add that she is thrifty, and a hoarder. She keeps all her clothes, dating from her Biba days, in an "extraordinarily big loft" and is known to haggle in markets on holiday abroad. "My mother had a stall in the market and I was brought up that way. Oh, I can't help it. And I save the butter papers to grease the cake tin. It's been instilled in me - I hate waste." Though these days, she has someone else to make the cake. "You're just as bad - electric, you go mad at," she adds to Bobby.

Though paying the bills can hardly be a headache. Cilla gleefully agrees that she has made a "lorra, lorra money!" Bobby, who is a solid-looking, dependably bearded chap, handles all the sordid filthy lucre. Like the Queen, Cilla has no truck with it. "I've never, ever worked for money. I would do what I do for absolutely nothing. The people who look after me have got the best deals for me - that's fine, I don't want to know about it. I've never signed a cheque in my life. I was given a cheque for pounds 500 once, as part of a prize, and I was so embarrassed, wasn't I, Bobby? I didn't quite know what to do with it. I am the old-fashioned housewife - if I am going to the supermarket in Gerrard's Cross, I'll have to ask Bobby for money." Though it's hard to imagine her asking Bobby for a tenner to pop out for a pack of frozen Chicken Kievs, or whatever they might eat in Buckinghamshire: she is so obviously extremely canny and in control.

And, again like the Queen, she is somewhat above politics, though in the past she has confessed to admiring John Major. "You're talking here to a person who hires a plane to go and see her family in Liverpool. I live like a Conservative. I am not a champagne socialist. I think that would be being a turncoat. If anything I would describe myself as quite liberal - but I wouldn't vote for them. But I can't live the way I live and then go down and put an `x' against socialism. Having said that, I don't follow politics at all. Bobby's the one. He tells me where to put the `x' and I put the `x' where he tells me."

Will Blind Date go on forever, till the entire population under 30 has been on it? (Cilla is already meeting "second-generation" contestants who have longed to take part since they were children.) "You'll have to ask Mystic Meg. The day you think `Oh, this is a drag', that's the day when you've got to pack in. But I am the original, hyper-active child that's never grown up. In my brain I'm thinking 29, then I look in the mirror and I see 53. I don't feel that old. To ask me if Blind Date will ever go off is a bit like asking me will I ever retire, and, in a word, the answer is no."

! The new series of `Blind Date' starts next Saturday at 7.15pm on ITV