Alan Mathison Turing was a British pioneering computer scientist; mathematician; logician; cryptanalyst; philosopher; mathematical biologist; and marathon and ultra distance runner. He was highly influential in the development of computer science.

During the Second World War; Turing worked for the Government Code and Cypher School at Bletchley Park; Britain's codebreaking centre. Turing's pivotal role in cracking intercepted coded messages enabled the Allies to defeat the Nazis in many crucial engagements; including the Battle of the Atlantic; it has been estimated that the work at Bletchley Park shortened the war in Europe by as many as two to four years.

Turing was prosecuted in 1952 for homosexual acts; when such behaviour was still criminalised in the UK. He accepted treatment with oestrogen injections (chemical castration) as an alternative to prison. Turing died in 1954; 16 days before his 42nd birthday; from cyanide poisoning. An inquest determined his death a suicide; but it has since been noted that the known evidence is equally consistent with accidental poisoning.

In 2009; following an Internet campaign; British Prime Minister Gordon Brown made an official public apology on behalf of the British government for 'the appalling way he was treated'. Queen Elizabeth II granted him a posthumous pardon in 2013. Pictures From History