Thanks everyone. They all bring back lots of memories now. The Honeybus one sounds as though its the earliest. I remember it well. Didnt realise they went back that far.
hp sauce use to have "in the summertime" by mungo jerry i think caburys chocolate biscuits had "theres a whole lotta loving" by guys and dolls (70's group david van day was a member) and not so long ago cadburys chocolate bars used phil collins song in the air tonight. but hey although not a pop song who can forget the shake and vac song lol