Battle of Britain period Air Ministry Spanner

An excellent issued example nicely marked with a large AM (Air Ministry) and Kings Crown property mark and dated 1940. The reverse confirms the dual size in BSW (British Standard Whitworth) in the old Imperial measurement scale devised in 1841. Interestingly one end has been damaged in use and skilfully braised so it safe to assume this spanner served its time back in the summer of 1940! measures 6.5" (17 cm)