This is a promotional, metal advertising tin for Smith's Crisps, with separate, non-hinged lid.
The design is from the 1920s when Smith's crisps first started out in Cricklewood, London. It was intended to be a shop display piece, sitting on the counters of local corner shops and prompting customers to buy what at the time, would have been quite a novel and interesting snack.
What condition is it in?
If you have any questions, just send an email to help@3bcshop.com.