TopGear airs on BBC2 at 8pm UK time on Sunday. That clip is from the 3rd episode, 7th season. Finalgear.com members are the primary ones cap'ing the episodes. They will also link you to the episode torrents.

*edit* by the way, while the Zonda and the Ferarri are media cars, that GT40 is actually Jeremy's personal car. The rest of the segment is great, with the running joke being the enormous fuel consumption of the GT40 compared to the others.