Pat's health has been slowly deteriorating in recent weeks and the reality of her condition is about to be revealed as she is diagnosed with a terminal illness, before taking a sudden turn for the worse.
As Pat lies on her deathbed in the soap's extended New Year's Day episode, viewers will see family, friends and foes all gather to say their goodbyes before she passes away.
Here, Pam chats about her final EastEnders scenes and reflects on 25 and a half years playing one of Walford's most-loved characters.
How have you found your final few weeks on EastEnders?
"It's been a busy few weeks on EastEnders, I think you could say. Emotional from the point of view of the performance and also tough from the point of view of the performance - and also it's been quite a challenge."
"I think it's going to be a very powerful week. The lead-up to the final hour is very powerful indeed - and I think that final hour is going to be fairly special, actually.
"It's something quite brave for EastEnders. It's intensive, it's very concentrated, and sometimes we tend to concentrate on the big, the events, the things that happen, the big geography and the big emotions - and we don't sort of go inwards as much as we used to in the early days.
"Back then, it was then totally based on people rather than events. Television has changed in general, so it's not surprising."
How is Pat feeling about her current health issues?
"I think that Pat is just concerned with the burden of what's happening domestically to the family, and she thinks it's actually causing a kick-back effect. She knows already that she has a heart condition. She's had two pacemakers fitted, so she knows, or she thinks she knows what that's all about.
"She is trying to solve the family issues first, and because of Norman, she's got the house into the situation where they may have it taken away from them."
Janine is also putting on a lot of pressure over the loan repayments…
"I'm sure in a strange sort of way Janine thinks she's doing a kind and right thing, in the Janine way! But the trouble is you never know where you are with Janine so that's even more anxiety for Pat."
"Janine and Pat's relationship is very complex. Pat unwillingly took on Janine. When Frank said, 'Let's get married' and Pat asked about his children, he said, 'Well the two oldest will come and live with us over the pub - the youngest will be in Manchester'. Pat wasn't up for being a mother of five, six children, so that was fine. But he dropped the bombshell when they got back from their honeymoon and said, 'By the way, Janine's coming to live with us'. Pat went fairly spare really, but having been given that responsibility, she then tried her best.
"But any child who is foisted upon a woman who is living above a pub who smokes and drinks is going to resent that woman. And she resented her like mad, she played up every which way. She wasn't vicious at that time, she was just disturbed. And I think it went from there, it went from bad to worse really."
How important is Ian to Pat's life?
"I think she's very realistic about Ian. She knows he's a materialistic little b**tard! I don't think if she had a choice of friends to make she'd say Ian Beale - she's seen him make a mess of his life.
"Strangely enough, despite being Pete Beale's son, the turning point for her was the fact that with such charity and grace, Ian took on a son that wasn't his. When Cindy was pregnant with Steven, I think that, in a strange way, made her respectful of Ian. So you know, deep down, she does think he's okay despite all his flaws."
"The trouble is most of them weren't her decisions. It wasn't her decision not to marry Frank - Frank was already engaged when they met. So that's why she spent many of her years trying to get over the grief that she wasn't with the man that she loved.
"Later everything that happened to her and him was not Pat's decision. It wasn't her decision that he walked out on her because he couldn't cope with the fire in the car lot. Well, it was her decision to marry Roy, but she thought Frank was out of her life forever - so it wasn't her decision that he came back and caused ructions."
But there was genuine love between Pat and Roy…
"A very gentle love yes, very gentle. They learned to tolerate and be accepting of each other and I think she thought, 'Actually, this is rather nice as I'm getting older. Yes I have a dependable man who is like chalk and cheese as far as Frank and Roy is concerned'."
After 25 and a half years, why do you think people love the character of Pat so much?
"It's strange because even in the early years I thought I'd get hate mail, but I didn't. And I think that what people liked was a vivacious go-getting person with an interesting history - and a person who under it all was really quite vulnerable."
"Most of the physical development of it, of Pat's image came from me. I love the idea that women of my generation and of that particular place and time that Pat came from - that sort of social place - tend to be stuck in their heyday. So I think that the blue eyeshadow and the bright pink lipstick was very much her heyday.
"When I first came in, the hairstyle was the fringe in the front down, and the hair lower down the neck. That was loosely based on a bus conductress that I saw. You know, it's ridiculous, isn't it? We actors are parasites, we feed on everything we're experiencing and seeing!"
Are there any particular storylines that stand out for you?
"There are probably so many highlights. It's so difficult after 25 and a half years to actually point out something specific. I think meeting up with Frank was probably one of them, which would have been round about '86 probably. She got a letter from him and went off with the women's darts team and she met him for lunch and reminisced.
"Another would be Frank and Pat's wedding. Then the affair when she was married to Roy and the consequent triangle, the 'You bitch, you cow' - all that."
"The strange thing about Pat and Peggy is that they loved to hate each other. Well, they hate to love each other! There are very few relationships in life which start at one point and automatically develop to the complete opposite. Most relationships go up and down. And that's what happened to Pat and Peggy.
"They didn't like each other because the men got in the way. And the first time there was a chink of possibility of a relationship was when Frank was supposedly dead in Spain. Which was a complete con, but it was as though a burden had been lifted from them. And the same thing occurred to a greater extent when Frank actually died. I think their relationship flourished after that point, because there was no longer the spectre of something between them.
"And they were both getting older, for goodness sakes. Peggy had medical problems and she started to feel her age. They could acquaint with each other. They had been there, done it, got the T-shirt. They understood each other's backgrounds. They still had their little blips when defending their families, but they were tight."
What are you going to miss the most about EastEnders?
"The people - I am definitely going to miss the people. The cast, many of whom are friends now and will remain friends, so that's fine. I won't miss them because I'll see them, not on a regular basis but I will see them.
"I'll miss everybody in production and beyond, because there's a very tight core of loyal people here - loyal to the show, loyal to each other and they've been in saddle for a long time and I've known them for a long time. We have wonderful camera crew, sound crew. They're probably the ones with the greatest longevity. Directors, but who knows, I might see them on the outside because directors do come and go."
"It's funny, because I'm not sure that I can answer this question until I actually put her down, which will be when my final scenes are transmitted. Maybe even after that, because obviously the aftermath will have a knock-on effect. So I don't think I can answer that until I can put the show away, which will be later in 2012, and then I shall be completely over it. Then my grieving process can start if it's going to!"
Will you be watching Pat's final episodes?
"Yes probably, although I may record it and watch it at a later date. Depends if everybody I'm with wants to watch it! I do hope it moves people. It always worried me at the time that I was doing it - I said this to the director - that I hope I wasn't being unutterably boring and playing one note. But I did work hard not to, and I hope that comes over and I also hope that people feel that my performance was geared for them to feel."
Pat's final EastEnders episode airs on Sunday, January 1 at 7pm on BBC One.