This envelope is an official First Day Cover (FDC) released by the British Royal Mail on June 16, 1987, to celebrate the Centenary of the St John Ambulance Brigade (1887–1987). The left-hand side showcases the large emblem of the St John Ambulance, bordered by its core principles like service, charity, and faith.
It holds a full set of four commemorative stamps depicting historical scenes of medical assistance and transport, officially canceled by a circular "First Day of Issue" postmark from Croydon, Surrey
