Doctor Who: The Adventure Games has been produced by a team drawing on the very best talent from TV and gaming. The interactive episodes are executive produced by Steven Moffat, Piers Wenger, Beth Willis and Anwen Aspden (BBC Wales Interactive), alongside Charles Cecil, one of videogaming's most revered creators. The games are being developed by Sumo Digital, one of the UK's best game designers. Stories and scripts are from Phil Ford (co-writer Doctor Who 'Waters of Mars') and James Moran (Severance, Torchwood Children of Earth). The project has been commissioned for BBC Online by the Vision Multiplatform team, headed up by Simon Nelson, and is being driven by BBC Wales Interactive.

Matt Smith and Karen Gillan have been digitally recreated in-game, and have provided full voice-overs. Music has been provided by TV series' composer Murray Gold. An additional cast will portray original characters and classic enemies.

Entitled ‘Shadows of the Vashta Nerada’, this fourth episode sees the first appearance of Steven Moffat’s brilliantly original monsters since their debut in Silence in the Library and Forest of the Dead.

Executive produced by Steven Moffat and written by Doctor Who writer Phil Ford (Shadows of Mars, Torchwood), the game sees the return of Matt Smith and Karen Gillan in digital form – as the Doctor and Amy face their biggest adventure yet.

Kicking off immediately following the cliff-hanger ending of episode three, Shadows of the Vashta Nerada sees The Doctor and Amy materialise just south of London (and about a 1000 miles to the left) inside an aquatic sea-bed colony called Poseidon. The game features a breath-taking plot which surrounds a real-world conspiracy – and, of course, takes place at Christmas.

“We’ve gone all-out for the season finale,” says Steven Moffat, executive producer Doctor Who. “Shadows of the Vashta Nerada takes place entirely underwater – something which would be impossible for the TV series, as water is so expensive. It’s thrilling, terrifying, educational and fun. Just steer clear of those shadows...”

Shadows of the Vashta Nerada will be available on Christmas Day.

James Moran's madcap script takes players on a frantic, funny and altogether surprising adventure which could only be told by a Doctor Who story. With full virtual likenesses of Matt Smith and Karen Gillan, and music from Murray Gold, this adventure is as much a part of the Doctor Who legend as the TV series.

Establishing new forms of drama is exactly what the BBC should be doing. By aiming these 'interactive episodes' at the broad audience of TV show - unique in British television, in that it encompasses at least three generations - we're aiming to encourage the family to gather round the PC or Mac in the same way they do the television. Driving computer literacy is a keystone of the BBC's public service remit and we expect Doctor Who: The Adventure Games to be hugely popular in the homes of Britain this year.

TARDIS will be soon available simultaneously on PC and Mac from the Doctor Who website (www.bbc.co.uk/doctorwho). The game will be available for no extra cost to UK households. Users outside the UK will be able to purchase and download it on the same date - details will be put on the Doctor Who website.