That's Brands Hatch in 1985, during the European GP.
Watson drove in Lauda's MP4/2B, since the world champion had injured his wrist. Didn't do much good to McLaren in terms of championship points, finishing 7th, even in an eventful race, that saw Mansell's first win, Prost coronated World Champion, a fantastic race by Rosberg climbing up to 3rd after a puncture following a get together with Senna (for which he took revenge later in the race...) and a superb drive by... Marc Surer!
I strongly recommend to any F1 fan to see the BBC's 40-minute video of the race. By the way, the page that hosts the video seems to be the same where Sebp found the photo... see how everything's related?