Derek Martin has been one of the most authentic working class voices in British film and television since the 1970s. Born Derek William Rapp in 1933, Martin was in the RAF for his National Service and took up a series of jobs including road worker, Smithfield Meat Market porter, and professional gambler, before entering showbusiness as an extra and stunt performer in a variety of programmes including Doctor Who. He retired from stunt work following an injury on Elizabeth I in 1971 and moved into acting. His most famous break out role was as t…