Spain. (Great Britain - Concessionary Mail). 1894. Envelope written from 'H.M.S. "Speedy", Vigo, Spain' addressed to Kent, England bearing Great Britain SG 172, 1d lilac tied by Foreign Branch obliterator with adjacent Vigo dispatch '15th Oct 94' and signed by the Commanding Officer, hand-struck 'T' with Great Britain '4d/ F.B.' hand-stamp on face and London arrival '18th Oct'.
On reverse endorsed "Sir will you kindly inform me the reason I have to pay fourpence extra for a stamped letter."
The payment of 1d should have been enough for concessionary mail (signed) available to solders and seamen on active service and the recipient queried the surcharge of 4d on this letter.