Airmail cover with manuscript 'Forces Air Mail' at top and boxed 'ORDERLY ROOM 8th Btln Kings African Rifles' military cachet in purple dated 13 AUG 1957 at left, illegally franked with 2 x 1954 10c green QE2 'Revenue' issue (Barefoot #9) one stamp cancelled by boxed 'T' TAX marking with DAR-ES-SALAAM cds dated 13 AUG 1957 struck away from the stamps and what appears to be an additional tax marking obliterated by a large black mark. Addressed to UK. Very unusual.