Not just any old Mess Tins

[Mk VII]

Aluminium was only used for them for a short time in 1938-39, as it became reserved for the aircraft industry, so early ones like that are quire rare now. Most wartime ones are tinplated steel (the tin melts when you try to fry things in them and molten globules of tin roll around). In 1945 they started to make them out of aluminium once again.
The maker is apparently N.C. Joseph of Stratford-on-Avon.
Pattern 1937 Web Equipment