One of the great London traditions takes place this Sunday - the annual London to Brighton Veteran Car rally - and it comes straight through Purley - more details here https://www.veterancarrun.com/news
. The first cars come through at about 08:15, and the procession of engineering marvels (if you like that sort of thing!) continues till about 10:00am. Purley Cross offers a great vantage point because the vehicles have to navigate through several sets of traffic lights, and starting and stopping these veterans can be a bit of a challenge, especially on a slight incline!
Here are some photos from last year when the heavens opened, but the forecast this year is much better.