TRELEVEN, ‘TREV’, HAYSOM was born in Langton Matravers, Dorset, attending the village school, followed by Swanage Grammar School. In 1959 he began working for his father, Walter, at St. Aldhelm’s Quarry, going to Weymouth College on a one-day-a-week basis. He continued his stonemasonry apprenticeship working for Benfield & Loxley, initially at Chichester Cathedral restoring the Arundel Screen and latterly in their Oxford stoneyard.

He was briefly a masonry instructor at the Oxford Polytechnic before returning to St. Aldhelm’s Quarry, running it until his retirement. The principal output consisted of quarrying Purbeck stone and Marble for monumental and general masonry and ecclesiastical work, including the restoration of many prominent buildings. He has served as Warden of The Company of Purbeck Marblers and Stonecutters, and given the annual Donovan Purcell lecture for the Stone Federation of Great Britain

In 2014, Trev was awarded an Honorary Doctorate from Bournemouth University. An authority on the stone beds and the fossil record within them, a cretaceous mammal has been named Dorsetodon Haysomi.