the civil defence & emergency service preservation trust now manages 11 of the uk's last gilbert mackenzie trench police boxes on behalf of a private collector. another blue police box of this style is preserved at the national tramway museum, crich, derbyshire. one of the trust's boxes stands outside the kent police museum in chatham, kent. and another at grampian transport museum. an original mackenzie trench box exists in the grounds of the metropolitan police college (peel centre) at hendon. there is no public access, but it can easily be seen from a northern line tube train travelling from colindale to hendon central (on the left hand side).