His work includes episodes of Clocking Off, Blue Murder and Robin Hood. Fay spent several years on the writing staff of Coronation Street, and in 2005 received the British Academy Television Award for Best Continuing Drama, sharing the BAFTA with Coronation Street producer Tony Wood and director Ian Bevitt. In 2007, Fay created the three-part ITV drama series Mobile.
Fay wrote two episodes of the third series of Torchwood, subtitled Children of Earth, which aired 7th and the 9th July 2009.. He will return to write for the shows' Fourth Series, a collaboration with the cable channel Starz, which is set internationally