Peter Cosslett was born in Cardiff, and initially worked in the merchant marines, where his fascination with the beauty and power of the sea first began. After the war he took up painting as a pastime, until a serious illness, which resulted in a leg amputation, made him decided to try to make a career out of his art, the thing he loved doing the most. He started to attend art classes at night school but was told that there was no more they could teach him, however, he persevered and taught himself through a process of trial and error, and eventually became one of the finest realist painters of his day.