Series 5 (Doctor Who)

Series 5, also known as Season 31 for clarity over Season 5, is scheduled for broadcast in 2010. It was commissioned at least as early as September 2007, along with five specials to be broadcast between Christmas 2008 and Christmas 2009.

2009 specials
Between the end of Series 4 and the beginning of Series 5 are five specials to be broadcast at various points in 2008-2009. Of the five specials, one has been scheduled for Christmas 2008, one for Easter 2009, and one for Christmas 2009, leaving two unscheduled as of July 2008. These five specials will be overseen by Davies and Julie Gardner, but traditional line producer, Phil Collinson will not be returning for them. All will reportedly star David Tennant.

Series numbering
Although it was initially thought that the "interval" season of specials might come to be known as Series 5, or Series 4.5, however at present it appears that the BBC will not be assigning a series "number" to the specials, much as the previous Christmas specials and mini-episodes do not technically belong to any particular season.

Writers
Russell T Davies is solely writing only the Christmas 2008 special and two others, but will co-write the others. One of the specials will be co-written by Gareth Roberts, and one will be co-written by Phil Ford. These particular specials will be historic in that they will be the first two episodes of the BBC Wales production of Doctor Who to formally credit a co-writer. With the inclusion of Ford, 2009 will mark the fifth straight year that Doctor Who has included at least one new writer for the show, and make Ford the only writer other than RTD himself to write for Torchwood, The Sarah Jane Adventures and Doctor Who.

Christmas 2008
Little is known about any of the specials as of mid-2008. However, the Christmas 2008 special was teased at the end of Series 4. The Cybus Cybermen are therefore known to be returning. Also, actors Dirvla Kirwan and David Morrissey are involved, as is a probable setting of Victorian England. ''Setting confirmed as Christmas Eve 1851 by a trailer shown at a San Diego Comic Convention in 2008. The trailer also showed what appeared to be a Dalek at one point.''

Series 5 proper
Davies will not be onboard in any capacity Series 5 itself. He has said he will not write a script for the series, nor be on hand in any advisory capacity.

The involvement of David Tennant — or indeed any other actor — has not been officially announced as of July 2008. However, Tennant is said to have "already made his decision and informed the BBC".

Nevertheless, it is known that at least two key people will be involved. Steven Moffat will be head writer and therefore likely assume Davies' executive producer title. Piers Wenger will relieve Julie Gardner of her executive producer title. Other than that, numerous rumours have circulated in the media over potential writers for the 2010 series, including noted graphic novelist Neil Gaiman, who was rumoured to have been approached by Moffat to write an episode.

No details regarding possible storylines have been revealed, although given the events of Series 4 there is widespread speculation about the possible returns of River Song (a character created by Moffat) and Jenny (a character Moffat is known to have prevented from being killed off). At the 2008 San Diego Comic Con, Moffat claimed that he had only started writing the season on the plane en route to the convention.

It has apparently been reported that David Tennant is leaving after the 2009 specials but there's still no confirmation.