It is simply called 'Theme from Randall and Hopkirk' and the composer was David Arnold.
Paul Whitehouse and Nina Persson (of The Cardigans), sung the vocal version of the theme. Originally Vic was meant to duet, but in an interview he conceded that his vocal contribution was 'a bit sh1t'.
thanks for answer do you know where I can get a list of the songs played in the programme, there was a song I liked when they were driving somewhere in a car?