I spent quite a while being taken in by the optical illusion of a terminus, otherwise this would have been quite easy. I think it's fairly obvious from the design of the train and the colour of the hand rails (visible inside the carriage) that this is either a Jubilee or Northern Line train. However, the facts that the number 53674 is legible and that Britain's got Tube geeks sufficiently tube-geekish to catalogue such things on the internet allow unambiguous identification with the Northern Line (if the train had been on the wrong line, then I'd have been stuffed). The obvious features of this station are the bridge and the tower block, so it's just a matter of looking at Northern Line stations which are above ground, hence Finchley Central (two and sixpence from Golders Green on the Northern Line).