BBC National Orchestra of Wales

 — often abbreviated as BBC NOW, and known in Welsh as Cerddorfa Genedlaethol Gymreig y BBC — has been the orchestra used by composer Murray Gold and orchestrator Ben Foster since series 2 to record the incidental and theme music forDoctor Who. Technically, their full name is the BBC National Orchestra and Chorus of Wales. Gold has used both the choral and orchestral aspects of the group to score Doctor Who.

History
The orchestra can be traced back to 1928 as the "Cardiff Station Orchestra", while the Chorus began in 1947 as the "BBC Welsh Chorus". Although it has always served as a broadcasting orchestra, it has equally been considered the national orchestra of Wales for most of its life. That is to say, it records music for programmes broadcast on television and radio, but it also gives public concerts for the people of Wales, and represents Wales by touring abroad. However, it took until 1993 for it to get its present name, which underscores its dual status.

Doctor Who-related programming
The inclusion of the orchestra in Doctor Who was largely because of the unexpected success of series 1. With an expanded budget for series 2, Julie Gardner could afford to indulge the inclinations of Russell T Davies and Murray Gold to fully orchestrate the show's score. The production team were able to emphasize the importance of the orchestra through a special concert in Cardiff in 2006, just prior to the premiere of The Runaway Bride. That concert featured the talents of the chorus as well, because the NOW Chorus was used extensively throughout series 2. However, the chorus was not the first chorus to be employed by Gold. He had used the Crouch End Festival Chorus briefly in series 1, before switching to NOW for series 2. But Gold then went back to Crouch End for series 3, and he gradually came to prefer them. As of series 5 it's almost certainly fair to say that NOW are the Doctor Who orchestra, while Crouch End are its chorus.

The orchestra has been of relatively less importance to the BBC Wales spin-off shows. They have never been used on The Sarah Jane Adventures, and were not a part of the first two series of Torchwood. However, they were used for Children of Earth.

On no DWU episode have they actually been credited for anything specifically to do with music. Instead their credit is always "With thanks to".