When Peter Heseltine died recently, many of his records were donated to the Oxfam shop in Huntingdon - where the Slim recording was discovered by manager Geoffrey Stalker.

He tells the Lynn News: "I rang the sound archive at the British Library, and as they were so very interested, I donated it to them. The British Library think this may be the only existing recording. It's of such historical interest, the team are very excited.