If you're thinking of the bah bah bah bah bah bah bahbah bahbahbah.....type of tune, its called 'Asteroid'. Used by Pearl and Dean advertising company for years now.
If you mean the 1970s Rank theme tune, the guy who composed it was on telly the other week making a new, longer version, it was great. Forgot the name thought. Put in 'Rank theme' as keywords and see what you get.