More than 250 items belonging to British scientist Alan Turing, including his doctoral degree and OBE medal, have been recovered in Colorado, 35 years after they were taken from the his secondary school in Sherborne.

Regarded as one of the greatest British mathematicians, Turing was persecuted for his homosexuality and died in 1954, aged 41, from suicide.

His reputation has been fully restored and celebrated when the World War II codebreaker was put on the new £50 note in July 2019.

A woman named Julia Turing, who claims to be his daughter and who, had stolen the goods and kept them hidden away in her home in Denver, having changed her last name from Schwinghamer in 1988.

Alan Mathison Turing attended Sherborne School from May 1926 to July 1931, during which time he boarded at Westcott House.

Between 1965 and 1967, Alan’s mother, Ethel Sara Turing, donated material to Sherborne School which formed the core of the school’s Alan Turing Archive.

The items were stolen after a woman asked to see the Turing archive at Sherborne. A note was later found which said: “Please forgive me for taking these materials into my possession. They will be well taken care of while under the care of my hands and shall one day all be returned to this spot.”

Based at Bletchley Park during WWII, Turing led a team of scientists to crack the German Enigma code, which is thought to have shortened the war by at least two years.

His seismic efforts during the war were acknowledged in the film The Imitation Game, directed by Morten Tyldum, in which Turing was played by Benedict Cumberbatch.

Headmaster of Sherborne School Dr Dominic Luckett said: “We are very proud to count Alan Turing among our most distinguished alumni.

“His crucial work as a code-breaker at Bletchley Park and his enormous contribution to the subsequent development of computing have become more widely recognised in recent years and we as a School are keen to do all we can to preserve and promote his legacy.

“As part of that we take very seriously our responsibility to look after those items in our archives which relate to his time at Sherborne School and his subsequent life and work.”

Court filings reported by the Boulder Daily Camera among other outlets, federal officials said they had recovered and were seeking the punishment of Turing’s degree certificate, the medal and photos, reports and letters from his time at boarding school.

Dr Luckett added: “With regards to those items removed from our archives, the matter is currently being dealt with by the appropriate US authorities and the School is unable to comment upon it at this stage.”