Newbie with an odd request

In the original british TV in season one In episode 3 around the ten minute mark Jessica is talking to grant about how some people don't get childhoods. There is this beautiful yet shril harmonizing humming playing in the background. I can swear I've heard it before, but when I checked the IMDb page and there was no music credits for the episode. I would really like to find it, and of anybody has any information on it let me know, thx