John has led tours to the battlefields of the American War of Independence, the Peninsular War, the Crimean War, the Great War, the Spanish Civil War and the Second World War. He is a member of the Western Front Association. He joined the Guild of Battlefield Guides in its infancy (Member Number 4) and was awarded Badge Number 10 in 2004. He has organised and continues to organize events for the Guild and is a long time member of the Guild Validation Team.

John Cotterill retired from the Army in 2014 after 37 years regular service in the Worcestershire and Sherwood Foresters Regiment and their successors, the Mercian Regiment. He has served all over the world including operational service in Northern Ireland (MiD), Bosnia (MBE), Iraq and Afghanistan. He has been leading battlefield tours since 1994 and has guided military groups, veterans, schoolchildren and others. He has been lucky enough to guide tours from Singapore to Stalingrad and from Tanzania to Tunisia.

John recruited and directed the two hundred volunteers who ran 'The Trent to the Trenches' which was Nottinghamshire's Great War Centenary Exhibition. It received over 100,000 visitors in the 4 months in which it ran in Nottingham Castle in 2014. He is currently heavily involved with planning the 2018 Armistice Centenary Commemorations in Nottinghamshire. He continues to advise local organizations and the media on Nottinghamshire and Derbyshire aspects of the Great War, most recently the participation of the Sherwood Foresters in the Easter Rising in Dublin. Between battlefield tours, of which he guides about twenty a year, he is a volunteer caseworker with SSAFA. John was born in Derbyshire and lives in Nottingham.