This amused and intrigued me so much I had to take a photo of it. It is an old "Unpaid Fares" honesty box in original Network South East blue. Clearly unloved, and unused, for a long time time, it remains in place quietly rusting itself out of existence in the age of Oyster cards* and penalties for not "touching out". It is situated at the exit from Chorleywood station down platform to the car park.

* Oyster is the smart card ticketing system used on public transport within London http://oyster.tfl.gov.uk/