John Henry Cound Brunt was born on 6 December 1922, on a farm in Priest Weston, near Chirbury, Shropshire to Thomas Henry Brunt and Nesta Mary Brunt (née Cound), and began his education at Chirbury village school. He had an elder sister named Dorothy (born 13 May 1920) and a younger sister Isobel (born 5 October 1923). When Dorothy was eight, the family moved to a farm near Whittington, Shropshire, where John grew up. As he became older, his fearless nature became more apparent; every week, he read the comic "Tiny Tots", which featured instructions on "How to teach yourself to swim". One day, he asked Dorothy to take him to the Shropshire Canal, which went through their farmland. Before his sister could stop him, Brunt had taken off all his clothes and jumped into the canal. When they finally arrived home, their mother wanted to know why he had no clothes on, and John responded that he had been teaching himself to swim. As he got older, his daredevil attitude became even more serious; on one occasion, he was found swinging himself along the guttering of a Dutch barn above the farmyard.