Executive producer

An executive producer is the head of the above the line talent on an episode, and is in overall charge of any episode's production.

Overview
In the 1963 version of Doctor Who, executive producers were largely not credited, because the Head of Serials (or the Head of Series and Serials) was the un-credited executive producer of not only Doctor Who, but all programmes in the department. The only year for which this wasn't true was season 18. In this case, the incoming Head of Serials asked Barry Letts to do his job for him on Doctor Who and oversee John Nathan-Turner's first year as producer. (REF: The Fourth Doctor Handbook) Hence, for that year only, an executive producer was credited on BBC-produced Doctor Who.

Since the 1996 tele-film, executive producers have been routinely credited on all DWU episodes. There have always been multiple executive producers on each episode of Doctor Who, The Sarah Jane Adventures, Torchwood, and K9 — except for the unusual case of the official BBC parody, The Curse of Fatal Death.

Different executive producers have traditionally had different production emphases. Russell T Davies and Steven Moffat, for instance, have been primarily focussed on the writing, though they have had the authority to make decisions on any production matter they chose. Julie Gardner and Piers Wenger have held an executive producer credit largely because they held a senior position at BBC Wales. In this way, they weren't too different from the un-credited executive producers of the past, like Shaun Sutton.

In contrast to the classic series, they have been much more involved with the workaday production of the show. They have made direct contributions to narrative and storytelling, as well. Gardner overrode RTD and insisted that the Tenth Doctor should leave Earth for the last time from the Powell Estate, to narratively "bookend" his first appearance on Earth in The Christmas Invasion. (PCOM: The End of Time, part 2) The "BBC Wales executive producer" has also had an active role in major casting; Wenger was directly involved in choosing Matt Smith (CON: The Eleventh Doctor) and Julie Gardner negotiated for the series 4 return of Catherine Tate largely without RTD's assistance. (REF: The Writer's Tale)