Chris Davies was an electrician for Doctor Who during series 2. During series 3 and series 4, he graduated to best boy on Blink and Turn Left, two double banked episodes for which the programme's regular gaffer, Mark Hutchings, was unavailable, forcing rearrangement of the electrical department's staff.
Davies was also best boy throughout the entirety of third series of The Sarah Jane Adventures, and for several episodes of Torchwood's second series.