MERVYN: I think the idea came from somebody in the comedy department, who casually said to the Controller of Drama "Wouldn't it be a good idea if...." The Controller did think it was a good idea, spoke to myself and Holby's Executive Producer, got it commissioned by the Head of BBC ONE and the rest is history.

MERVYN: The challenges were huge from who was going to write this thing, how we were going to do it, what story would we tell etc before the really difficult stuff of how to get together two large casts who work 120 miles apart in Elstree and Bristol.

At the heart of it was the problem of two large shows which work continuously 52 weeks of the year, being interrupted and brought to a halt for a short period (two weeks). This released a number of characters to appear in the special, but then we had to restart the two shows, sometimes using those characters when available, but mainly using the other characters who weren't in the special.

The schedulers from both shows had a nightmare time, but kept smiling as ever and deserve medals for making it all possible.