Durnford School was an English preparatory school for boys which opened in 1894^[1] on the Isle of Purbeck in Dorset.

The school occupied Durnford House, in the High Street of the village of Langton Matravers near Swanage, and was notoriously spartan and uncomfortable.^[2] Ben Macintyre described Durnford as "a traditionally brutal prep school [which] epitomised the strange British faith in bad food, plenty of Latin and beatings from an early age".^[3] "Strip and swim" was the morning ritual for the boys – watched by headmaster Thomas Pellatt – into the sea from Dancing Ledge on the coast in 1898. Later, Pellatt had quarrymen blast out a pool in the rocks of Dancing Ledge, for his pupils to swim in.^[4][5] Pellatt, who co-wrote plays that appeared on the London stage under the pseudonym Wilfred T Coleby, published his reminiscences in 1936.^[6][7]

The School closed at the onset of the Second World War and the Durnford boys were transferred to another prep school in the village, the Old Malthouse. In 1939 the site became a ramshackle out-station of the Telecommunications Research Establishment, where Britain's radar systems were devised from 1940 to 1942. The school's location is shown on a map of radar sites scattered throughout Dorset during the period.^[8]

In 1948, when the British army gave it up, Durnford House was acquired by the owners of the Old Malthouse. The main buildings were variously pulled down or sold, leaving the Old Malthouse with the grounds, which were levelled for playing fields. Durnford House itself still stands.