Dan Pascoe, the BMW-proof British cop, says in this BBC interview that chasing after the car that hit him was just a snap decision. Streetside Stig got a more realistic narrative of the crash from Pascoe's point of view:
"Hey there, mate, stop the car, all right? Right. Well...wait, no stop, there. Oh! Look at that, you've crashed your poor M5! Are you quite all right? Oh, you sport, you! Still running, eh? Haha, well, lets see- ("You all right, Sergeant? Okay, I'm gonna chase after the little fellow, then, get this sorted.) let's see if I can catch you, hoo hoo! Oh, come on then, old chap, I know you can run faster than that. Make a go of it, eh? No? All right, well, I hope you don't mind a nip of voltage to the neck. There we are, old chap, that will relax you straight down. There's a good lad. Care for tea when we get back to the station?"
Dang. British people are so polite.