This program is shown on Saturday nights on PBS here in the US; I've read a lot of British people go on and on about the show, so I actually tuned in one night to see what the fuss was about. I couldn't tolerate a full ten minutes of it before switching the channel.

Did they have The Walker Brothers' 'The sun ain't gonna shine anymore' playing on the pub's jukebox while Peggy was delivering her scolding?

I wonder whether there's a spot of backstage tension between her and the writers. Perhaps she had angered them in some way — by murdering most of her lines, for instance — and this is their revenge. Utter genius.

Sadly, my EastEnders mole no longer works on the programme, but she told me that there was no shortage of volunteers to write Martine McCutcheon's death scene a few years ago. So I suspect you're pretty much on the money here.

(Actors frequently get their scripts at the absolute last minute thanks to insane production schedules - EastEnders has to churn out two hours per week, every week - so there's plenty of scope for subversion like this, as there's no time to complain)