Peter Henry Lenton was born at New Hunstanton, Norfolk, on 20 September 1910. He was the son of Walter Henry Lenton, a pharmacist and was educated at King Edward VII School at King's Lynn where he won the Gold Medal given by George V and personally presented to him by the King. After leaving school

He was born in London in 1912, and received his early education at Doon House Preparatory School, Westgate-on-Sea, Kent. He then went to Uppingham and was promoted to the scientific sixth form in his fourth year. In 1930 he was enrolled as a medical student at the London Hospital Medical College.