Joan Rivers spilling acid on the red carpet

"Come anywhere nearer and I'll bite you in the ass." Joan Rivers is doing battle with a photographer in her suite at the Ritz.

"But Joan, you look fabulous," he says, trying to reassure her.

"Yeah, right," she replies acidly. "Who are you trying to kid? At my age it's all you can do to look alive. Now keep your distance or you'll crack the lens."

As anyone who has seen the New York comedian in action will know, this is a classic Rivers exchange: sour, sarcastic and self-mocking.

Still, you can see her point. Though physically she's a lot smaller than you expect - even in stiletto heels she barely reaches my chest - from a certain distance she is really very glamorous.

Look closer, however, and it all gets a little otherworldy. While her eyes seem to have been yanked simultaneously upwards and outwards, giving her face an expression of frozen astonishment, her nose has been chiselled, chipped and sculpted into a perfect Upper East Side ski-jump.

Add to that the false eyelashes and the fashionable fly-away hairdo and the overall impression is of Barbie caught in a wind-tunnel.

Rivers, at 71, is the first to poke fun at her efforts to stay young. She says her best friend is Botox. Her 3-year-old grandson, Cooper, calls her Nana Newface.

It's very apt that she will play a patient in Nip/Tuck, the TV drama series set in a plastic surgeon's clinic.

Rivers learned early on in her career that if you dish it out you have to be able to take it.

Self-deprecation is an extremely effective defence mechanism - there's nothing that anyone else can say about her that she hasn't already said herself.

Most impressive is Rivers' ability, after 40 years in the business, to stay ahead of the game. During the 80s she would talk about faking orgasms and visits to the gynaecologist. Now it's all body fluids and sagging genitalia.

Where Elizabeth Taylor and Martina Navratilova were once her prime targets, these days the biggest tongue-lashing is reserved for the Hilton sisters ("You know you're gonna catch something with them") and Monica Lewinsky ("Oh God. One of the all-time stupidest bitches").

Rivers swells with pride when relating how, on the British show Live at the Apollo, her jokes about terrorists and September 11 widows were cut out by the BBC on grounds of bad taste. "If you can't talk about that, what the hell can you talk about?"

Since her stage debut in the late 50s, holding forth about the importance of marrying for money and looking your best to keep your husband, she has been accused of setting the cause of feminism back at least 50 years.

"What nonsense," she barks. "I've worked harder for women's rights than most. I've broken every barrier there is to break. As I always say in my show, 'Tell me it's not true'. Don't tell me you don't want to have somebody to love you, because that's bullshit. Don't tell me you don't want to look good, because that's bullshit too.

"I once had a big fight with [the writer and activist] Gloria Steinem, who sat there and told me how wrong I was. Don't misunderstand me, I think she's wonderful, we've marched together. But you have to face life too.

"I said to her, 'You're sitting here, you've just come from a waxing, your hair is bleached, you look beautiful. You've probably had a nose job. And what is so terrible about that?"'

Rivers insists that she's a keen advocate of family values. "If you can find some rich old pig to sponsor you, let me tell you, this is heaven. And then you can do what you want to do. I'm still looking for my own Onassis. I know that out there there's some rich guy willing to support me."

And you'd give it all up for a man?

"Well, perhaps not," she reflects. "But my rich old pig would say, 'Joanie, Joanie, you do what you want. Sponsor a movie? Of course, darling. You want to star in it? Well, why didn't you say so?"'

As well as being the most straight-talking woman in show business, Rivers is also among the most hard-working. Along with the stand-up and a chat show, The Joan Rivers Position, in which she appears as an agony aunt, a large part of her time is spent flogging costume jewellery on the American shopping channel QVC. She has also branched out into cosmetics and skincare products.

More recently she and her daughter, Melissa, have carved a niche conducting red-carpet interviews before Hollywood awards ceremonies during which they cast an acerbic eye over celebrities' sartorial habits.

You mean they actually come over and talk to you?

"Why wouldn't they?" says Rivers. "Usually the bigger they are the more they can relax and laugh about it. Julia Roberts isn't going to get upset if I don't like her dress. Those four Sex and the City girls - they think it's hilarious.

"Remember, we're only talking fashion, so let's calm down here. But there are the middle-ranking ones who are very insecure about themselves and who take it seriously.

"Kevin Costner became furious because when he brought his fiancee over, I said 'Let's have a look at the ring'. I mean, you couldn't find it. It made all the papers the next day. Come on, the man makes millions. He should just laugh it off."

Rivers' unstoppable riffing, by her own admission, masks a deep seam of insecurity. Even now she's terrified that the work might dry up, that the rug could be pulled out from under her feet.

"It's happened before, twice, so there's no reason why it shouldn't happen again. It's a very transient business. You can't pause for breath in this industry. You can't afford to take your eye off the ball for a second."

In 1988 the television station Fox pulled the plug on Rivers' late-night chat show after a dip in the ratings. Not long after, her British-born husband and manager, Edgar Rosenberg, who was depressed after having bypass surgery, checked himself into a hotel and committed suicide.

The finger of blame was immediately pointed at his wife, from whom he'd just separated.

"It was awful, just terrible," recalls Rivers. "I was crucified by the press and my daughter stopped talking to me. Thank God we're very close now. After that there was no work, so I had to leave California, go to New York and start over."

After months of therapy, Rivers was back on her feet and launched her jewellery line, and by the mid-90s Joan Rivers Worldwide Inc was turning over US$25 million ($36 million) a year.

But her career was to fall apart a second time when her business partner absconded with all the profits.

"You wake up at 65-years-old and realise you owe US$38 million ($54 million)," Rivers says. "At that age, you can't turn tricks. To get my name back, I had to pay off the shareholders. It was terrible. But I've got a great lawyer who got me through it. Twice a year he comes to my house and stands on a pedestal and we all bow down."

Though she still goes on the occasional date, Rivers believes she'll never marry again. Two years ago she ended a nine-year relationship with Orin Lehman, a New York banker.

"As you get older you get cynical and it gets harder to fit other people into your life. I'm working very hard now because there's no one I want to stay home with.

"When I get a chance to go on tour, I jump at it. I get to go to all these places that I've never been to before, like Wales and Devon. We're going to Torquay on this tour. I've never been there, I hear it's full of old people. For all I know I could meet my Onassis there and stay there until I'm dead."

Rivers, who was born Joan Molinsky in Brooklyn, New York, to Russian immigrant parents, says her biggest inspiration has been her mother.

"She was very strong, never complained about anything. It was years after she was dead that I realised it wasn't that great a marriage, and that she was very lonely. She just held her head up and got on with it.

"She looked like a great dowager, always dressed in pearls. I thank God that she lived to see me successful."

When she was a teenager her parents warned her off comedy - they felt it was an unseemly occupation for a woman - and at their insistence that she went to university. Rivers attended New York's Barnard College and, in 1954, graduated with a degree in psychology and anthropology.

In her early years as a stand-up she played small New York dives where a hat would be passed around at the end in lieu of payment.

For a while she worked as an actress, appearing in low-key productions alongside Barbra Streisand, Bill Cosby and Woody Allen.

Her big break came in 1965 when she appeared on The Johnny Carson Show, although it wasn't until 1983 that the show broke with tradition and named Rivers as its permanent guest host, a position she held for the next three years.

Even now, Rivers says she gets stage fright. When she walks on stage she gets her warm-up act to award marks out of 10 on the audience mood. Anything above seven is great, five is workable. Anything less than that and she knows there's hell in store.

Her nerves are even worse when she's acting.

"I hate anyone coming to see me in the dressing room before a show. I've been on Broadway four times and I still think I'm going to forget my lines."

It's with a typical mixture of haughtiness and anxiety that Rivers says retirement isn't an option.

"They'll have to drag me off the stage in a box. I have a lifestyle to maintain and that costs money. If I stopped work I'd drive myself crazy thinking about all the opportunities I'd missed.

"I have this running joke with my daughter. I tell her, 'I haven't peaked yet'.

"Anyway, I can't have all those other comics getting too big for their boots. If I have one more of them come up to me and say, 'I owe my whole career to you,' I still think, 'Listen you little bitch, I'm still going to wipe you off the stage'."

She pauses, leans forward in her chair, and whispers conspiratorially: "And I always do."

- INDEPENDENT