Here is the clip: https://clyp.it/bkwufqdz
It is a brief excerpt of some classical-sounding piece used as backing music in James May’s Cars of the People, and unfortunately James is talking all over it so it’s not that easy to hear. Sounds like early 20th century? Or could it be John Williams? It reminds me of the Close Encounters score, although listening to some of that on YouTube I couldn’t find it.