Broadcast has a long and interesting interview with Will Cohen (currently Executive Producer at Milk, doing pretty much the same job as he did back when the Doctor Who VFX people were called The Mill) about special effects on Doctor Who. Full article at the link."As a measure of just how pioneering it was, when the BBC tendered Doctor Who’s visual effects work in 2004, there was virtually no reference material available. A decade ago, VFX wasn’t really present in UK drama...the only VFX for TV were graphics sequences in docs or reconstructions in drama docs. Maybe there would be a couple of shots compositing a pyramid outside a green-screen window on an episode of Poirot. It was all quite naïve.”
The Mill itself, while it had worked on a good many advertisements and feature films, didn't have much experience with television and keeping up with the DW production schedule was quite difficult for the first few years.
“Drama producers now value VFX because it suggests production values of ambition and scale...Where TV VFX was once considered cheap or shoddy, the dividing line between feature film and TV is now very fine and Who can claim to have embedded that in UK TV production culture.”
Bafta-winning sequence in "The Fires of Pompeii" of the volcanic eruption.