Her storylines have included a series of failed romances, most notably a non-lasting marriage with established character Frank Butcher (Mike Reid) and then a short-lived wedding to her brother-in-law Archie Mitchell (Larry Lamb).

She has also been central to several plotlines revolving around health issues; launching a hate campaign against the HIV positive character Mark Fowler (Todd Carty) before later going on to make amends with him when she is later diagnosed with breast cancer, which she recovers from; a longstanding feud with daughter-in-law Sharon Watts (Letitia Dean); an on-off rivalry and companionship with her frenemy Pat Evans (Pam St Clement); and clashing with many villains such as Frank's troublesome daughter Janine Butcher (Charlie Brooks) and gangland boss Johnny Allen (Billy Murray).

Chat show host Chris Evans of Channel 4's The Big Breakfast made a public broadcast instructing viewers to fax or phone the BBC with pleas for Windsor's instatement.

"[11] In an interview with the Walford Gazette, a US-based newspaper dedicated to EastEnders, Windsor commented on her casting: "I was thrilled, I could rest my tired bones working on a marvelous television show that I deeply respected.

[9] Mark Lawson for The Daily Telegraph has stated that five million extra viewers watched her first scenes, reporting that initially: "The critics said that she lacked the 'brassiness and vulnerability' for soap acting and that, stripped of her bubbly image, 'nothing much of interest was revealed'.

"[11] Windsor has commented of the impact of her pre-existing celebrity status: Wendy Richard [who played Pauline Fowler] certainly had name value but I suppose it was regarded differently because she was part of the original cast.

"[16] In a 2009 radio interview with Dale Winton, Windsor said three people have influenced her portrayal of Peggy: Violet Kray (thus retracting her earlier statement), her own mother, and the actor Mike Reid, who played her on-screen husband Frank Butcher.

"[19] In Lesley Henderson's book, Social Issues in Television Fiction, an EastEnders researcher explains that: "A lot of illnesses [...] translate quite readily into strong dramatic material", and the experience of being hospitalised or waiting on test results is something everyone can identify with.

"[19] Producers decided to use Peggy in the breast cancer storyline, conforming to a soap opera tradition of reserving strong roles for a firmly established middle-aged matriarch.

[19] The audience were familiar with Peggy's history, knew that her first husband had died from cancer, consequently making her fear hospitals, and she had: "the right mentality for [the story theme], which was about 'a woman who discovers a lump and then refuses to accept that anything's wrong'.

Suddenly she was in a new environment in a hospital and had a huge medical crisis to go through, so that allowed the character to grow and expand in many ways...There was also fairly major moments [...] with Peggy and [her boyfriend George Palmer (Paul Moriarty)].

[20] BBC Production chief executive Matthew Bannister praised Windsor's portrayal of Peggy coming to terms with a mastectomy, commenting: "It's brought a good deal of comfort and help to us and a lot of other people.

Their coupling was part of producer Matthew Robinson's plan to place the focus of the soap back on to the Butcher and Mitchell families, while various other long-running characters were axed following a decline in ratings.

The episode, written by Tony Jordan, featured what the Sunday Mirror described as one of "the most vicious fights ever filmed by a soap",[24] with both throwing glasses at one another and Pat slapping Peggy across the face exclaiming "You bitch!"

[27] Together Frank and Peggy ran The Queen Victoria, and were involved in various family and business crises, including a "tug-of-war" for their public house with "cuckoo-in-the-nest" Dan Sullivan (Craig Fairbrass).

[29] The pair enjoyed a liaison on a Spanish beach during a week-long August special set on the Costa Blanca, which saw Frank and Peggy go away with Pat and Roy and Terry and Irene Raymond (Gavin Richards and Roberta Taylor).

Her full return was announced in January 2005, with John Yorke, the BBC controller of continuing drama series, stating he was "delighted" as "[Peggy] is a hugely loved character and one we think will be stirring things up from the moment she steps back into Walford.

Johnson commented on his appearance: "It was, of course, a tremendous honour to step inside that most venerable of London landmarks, The Queen Vic, and share a scene with another of the capital's icons, the fabulous Barbara Windsor.

"[43] Executive producer Diederick Santer stated: "We couldn't let the visit pass without the Mayor entering London's most famous pub, The Queen Vic, and meeting its formidable and politically active landlady Peggy Mitchell.

After thinking long and hard about it, I realised that it is time for me and the audience to say our final farewells to the lady who I have loved for many years and I thought that whilst [executive producer Dominic Treadwell-Collins], who I adore, is still in charge I want him to be the one to oversee it.

Eric fell in love with a glamorous woman called Maureen Loftus and planned to elope with her, but he changed his mind at the last minute – unable to desert his family, who he grew to resent.

[13] Peggy makes her first appearance in Albert Square when her son, Grant, decides to reenlist with the army and returns when her daughter Sam's desire to escape from her family causes her to elope with Ricky Butcher (Sid Owen), at the age of sixteen.

She also instigates a hate campaign against local resident Mark Fowler (Todd Carty) when she discovers he is HIV positive, and in doing so clashes with his mother Pauline (Wendy Richard) on several occasions.

While trying to exonerate Sam and reclaim ownership of the pub, Peggy is surprised to learn that Johnny is now the square's new gangland kingpin and the two establish a feud when he also wishes to buy The Queen Vic.

Three months later, Peggy flies into London to visit Phil in hospital, and encourages him to get rid of Carl White (Daniel Coonan) – an ex-conman who seeks to take over the Mitchell business empire.

Peggy is also in on the secret that Ben's mother and Phil's ex-wife, Kathy Sullivan (Gillian Taylforth), had faked her own death nine years ago and wants to return to Walford.

After settling old feuds with Sharon and Stacey, and having one last drink at the Queen Vic, Peggy begins hallucinating the smell of cigarette smoke; this eventually manifests into a vision of Pat.

"[19] The storyline also received media criticism, for the use of a breast care nurse, who was used to counsel Peggy and translate medical terminology into lay terms for viewers; a character who could provide both a dramatic and educational purpose.

Paul Bignell and Cole Moreton for The Independent refuted the accusation, naming Peggy as an acceptable role model for her devotion to her family, protecting her nieces and loving her sons despite their numerous misdemeanours.

In the BBC's Big Impression, impressionist Ronni Ancona performs as Peggy, shuffling around on her knees to exaggerate Barbara Windsor's petite height, and regularly using the catchphrase "Get outta my pub!"