The Fourth Dimension
The Next Doctor
The location filming for The Next Doctor in Gloucester proved so popular that crowds of over 1,000 people gathered on some evenings. Quite a tricky situation when you're trying to record top secret stuff!
The Cyberleader sports a brain-revealing helmet, similar to the to the converted John Lumic/Cybercontroller from The Age Of Steel. The helmet's face has been painted black, however, possibly a design nod to Kroton The Cyberman, who appeared in comics strips in Doctor Who Weekly/Monthly.
Jackson Lake's TARDIS features a bell in its basket. We suspect that this is a small scale version of the Cloister Bell that announces danger in the real thing.
Russell T Davies chose the name Rosita for the Next Doctor's companion, because it contained elements of 'Rose' and 'Martha'.
Dervla Kirwan wore special black contact lenses for the scenes of the transformed Miss Hartigan. Because the lenses didn't completley cover her eyes, however, special effects wizards The Mill had to electronically paint out any glimpes of white eyeballs that appeared in shot.
Take It To The Bridge.
The impressive shots of the Cyberking had to be fixed by The Mill after Producer Susie Liggat spotted that the CGI model of 1851 London contained Tower Bridge - several years before it had been built!
David Tennant and David Morrissey have previously worked together on the acclaimed BBC drama Blackpool. At one point, David Tennant's character can be seen walking past the Doctor Who exhibition in the town!
The flashbacks of the previous nine Doctors marks the first time that William Hartnell's First Doctor has appeared on the show on Christmas Day since 1965's The Feast Of Steven - a festive instalment of epic adventure The Daleks' Master Plan.