Guildford, London (SW) A3
10
Gatwick Airport symbol, Leatherhead, Reigate M25

Also leave here for Portsmouth, because that's where the road goes. One of the better radial routes is to the left - the A3 makes a valiant attempt at the job, three lanes wide and grade separated for much of the way, but sadly gives up and turns into a single carriageway road before the job is finished. Just like most of the others, then!