Another year, another spectacular explosion destroying Casualty's accident and emergency department and plunging into smoky peril some of Holby City hospital's best-loved doctors and nurses. Though it sometimes feels as if infernos occur with a ridiculous regularity, the blaze that engulfed the A&E before Christmas wasn't simply a device to kill off some characters and create an end-of-series cliffhanger.
When the smoke clears, Holby's A&E will have been transplanted from Bristol to Cardiff and the BBC's purpose-built, state-of- the-art, ten million pound drama facility, Roath Lock.
Just how much of that investment the huge new Casualty lot cost, the BBC won't say, but it's evidently a significant amount.
As well as new colour-coded areas within the hospital - the reception area's yellow, the resuscitation area purple - there's an impressive outdoor set. As well as a cavernous ambulance bay, there's a terraced street, a plaza with a pub, a solicitor's and a bookie's, a new hospital entrance and even a memorial garden for the medical staff to spend moments of reflection between treating Britain's most accident-prone citizens.
Inside the Roath Lock studios - which cover 170,000 sq ft, the size of three football pitches - there's a plush prosthetics room and a prop store that, with its array of furniture and ornaments, resembles the world's biggest charity shop. If charity shops sold polystyrene gravestones.
It's all a dramatic change from the drama's old Bristol base, which was located on a dingy industrial estate.
"Bigger sets mean fewer location days," explains executive producer Johnathan Young. "Which ultimately saves money and means that when you do go on location, you can have bigger stunts and spectaculars - something audiences have come to expect from Casualty."
But for all this investment, there's one thing Young hopes viewers won't notice, even with the drama now in HD, another reason for the move. As odd as it sounds, it's the move itself.
"For the audience, Holby is Holby. It isn't Bristol and it isn't Cardiff. So we don't want the audience to think, 'Oh look, Casualty's moved.' It's definitely not something we want the audience to pick up on-screen."
While acknowledging the irony of spending millions for Casualty to look exactly the same, Young is adamant that the move from Bristol to Cardiff will benefit the show.
"There had been a drift away from Casualty's story-of-the-week and towards a more serialised element, so we're making sure that every episode delivers a satisfying, self-contained story. That's what the audience wants from Casualty and that's what we want to deliver."
And audience satisfaction is, as Young points out, priceless.
Casualty is on Saturday at 8:40pm on BBC1
This is an edited version of an article in the issue of Radio Times published 3 January 2012