Chirpy Cockney sparrer, bubbly blonde sex bomb, cheeky girl, national treasure, lord luv a duck Londoner and gangster' s moll - to this list of dog-eared descriptions of Barbara Windsor we can now add "survivor".   Her return to EastEnders as Peggy Mitchell will not only give the ailing soap a much needed kick up the ratings, it will also be a triumph over severe adversity for the actress. Two years ago a taxi she was travelling in collided with the back of a van. Windsor wasn't wearing a seatbelt and she was catapulted forward, smashing her head so badly she was severely concussed.  Shortly afterwards, she was discovered to be suffering from Epstein-Barr virus, a rare disorder that attacks the immune system, and was bedridden for nine months. Having only in the last few years managed to revive her career with EastEnders and her emotional life with a new young husband, Scott, the double whammy plunged her back into the depths of depression from where she contemplated death, if not actual suicide. With care from Scott, and health advice from the unlikely source of Michael Winner (who knew other Epstein-Barr sufferers and recommended alternative remedies that she eventually took), Windsor recovered.

Now she is more like her old self. In fact, she is more like her younger self as she has treated herself to a £14,000 necklift which makes her look at least a decade younger than her 68 years.  Half music hall chorus girl, half panto actress; she learnt her chops on stage, forged a nationally identifiable character in Carry On movies, survived a couple of scandalous liaisons and has since managed to make good use of all this baggage in a few serious roles and, lately, as the owner of the most famous boozer in Britain, The Queen Vic in EastEnders.

On one hand she is the poster girl for the McGill generation - a postcard cutie in a bikini two sizes too small. On the other, she is a known associate of villains and has been caught up in nefarious dealings not normally associated with the great and good of British entertainment, with the exception of fellow EastEnder Leslie Grantham.

There was a time when it appeared as if Windsor was born to inspire lechery - in the Carry On movies she always looked as if she had just got out of, or was just about to leap into, bed. She had the dirtiest laugh since Sid James who chased her gleefully all over the sets of the Carry On films until he eventually caught her. Only a few years ago, I bumped into her in Soho House when she was dressed to kill and she flirted and chatted like a girl, unleashing that laugh so shamelessly dirty that even her companion Dale Winton blushed.

Barbara Ann Deeks was born on 6 August 1937 in Shoreditch to a dressmaker mother and a bus conductor father. Her mother had aspirations for her only child and spent her savings on elocution lessons. Young Barbara was also expected to go to university as she was considered bright at school. Her experiences at Madame Behenna's Juvenile Jollities troupe and, later, Aida Foster's dramatic academy in Golders Green were enough to ensure her path would not be an academic one.

At 14 she made her professional stage debut at the Wimbledon Theatre pantomime with the Eleanor Beam Babes. By the time she auditioned for Joan Littlewood's career changing production of Fings Ain't Wot They Used To Be, aged 20, Windsor was a stage veteran.

The intervening years had been busy. She danced, sang and generally added to the gaiety of clubs and theatres in Soho in the 1950s, whether performing in revue and cabaret or singing in Ronnie Scott's Jazz Band.  The post-war London club scene was a thing to behold. Establishments such as Winston's, Churchill's, The Astor, The Celebrity and The Edmundo Ros Club drew personalities and stars from politics, entertainment and the underworld. Windsor and fellow entertainer Fenella Fielding were "the show", while Christine Keeler and Mandy Rice-Davies were the hostesses. During this period she encountered people such as Victor Mature, Diana Dors and Darryl F Zanuck. She also met any amount of London villains.  Clearly, such regular proximity to London gangsters under such uninhibited conditions created an attraction which she has barely been able to shake off. She married Ronnie Knight - a convicted criminal and all-purpose hard man - in 1964 and stood by him for 20 years. They were accompanied on honeymoon by her good friend Kenneth Williams, his sister and mother, which sounds like a Carry On film waiting to happen.

The recklessness of her teenage years is revealed in her confession that she had a fling with Charlie Kray "the handsomest of the brothers" at the same time as she was going out with Ronnie Knight. Now on her third marriage - to long time friend and lover Scott Mitchell - she has managed to pack in a lot of extra sexual escapades during her prime, if her memoirs are to be believed. "Once I discovered sex," she wrote, "I assumed you just did it. Nobody told me otherwise." One consequence of this highly active period is that she'd had four abortions by her early twenties.

Oddly enough, there is a strong trace of snobbery inherited from her mother. Like many people of a certain generation and attitude, she has a combination of prurience and shameless liberalism. She is quite happy to be associated with the "What a Lovely Pear" smut of Carry On films but refused to make any more after Carry on Dick because they were "dirty". When there was an attempt to revive the franchise in the mid 1990s with Carry on Columbus, Windsor turned it down after reading the script and "went out and got rat-arsed".

This strange collision of West and East End continues today and can still be heard in her accent which veers from Cockney to Grande Dame across a sentence. It is as if the elocution lessons were halfway successful. And her admission that one of the few things she regrets in her life is that she has never done a porn movie comes as a bit of a surprise. But even her explanation is tinged with a deranged innocence: it was because, she says, she would have liked to have had a record of her young, sexy body to remind herself of what she looked like.

Given that she was only in nine of the 31 Carry On films her impact has been extraordinary. Whether it be the wiggling walk of her nurse in Carry on Doctor or the iconic moment in Carry on Camping when her bra pops off during a keep fit class, she embedded herself in the British consciousness as the dizzy goodtime blonde with the dirty giggle and a chest according to Kenneth Williams "like a confectionary counter".

Perhaps Windsor's most significant assets are less obvious - her vulnerability and her capacity for survival. She survived dalliances with gangsters and marriage to a villain, survived an affair with Sid James and the release of a duet of "The More I See You" with Mike Reid. Now she has survived a crippling illness to reign once again as Queen of Soaps as Peggy Mitchell in EastEnders - a role for which she was originally considered too "well-known". In fact, the very public travails of her life and the details therein make her the perfect EastEnders ratings-booster as Barbara Windsor MBE is, to all intents and purposes, the real thing.