Number 645 in a series of caches where a red telephone bpx is in close proximity to a red post box.
The only rules are that they have to be able to be photographed together, be not more than 100' apart and the 'phone box must be red.
This telephone box was 'Cards Only' for several years, but it has been closed permanently now. However it still fulfils the criteria, so enjoy it while you can.