Chris Davies was an electrician for Doctor Who during most of the RTD era, beginning with 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 the third series of The Sarah Jane Adventures, and for several episodes in Torchwood's second series.