Some consider Turing to be the father of what we now call artificial intelligence. Some consider Turing to be the father of computer science. What is undeniable is that without Alan Turing, it would have taken far longer to break the Enigma code, an encryption code used by the Third Reich during the Second World War.
Unfortunately, despite his efforts and success in saving his home country (the United Kingdom), this was not enough to stop the government in 1952 from prosecuting (and eventually convicting) Turing for homosexuality and "gross indecency" as homosexuality was illegal in the United Kingdom at the time. Turing was faced with either being incarcerated or being placed on probation on the condition that he submitted to chemical castration (given female hormones to suppress his sex drive) and he chose the latter. As a result of his conviction, Turing was unable to work with the government.
In 1954, Turing was found dead by his cleaner. The death was ruled a suicide via cyanide poisoning.
In August 2009, a petition was circulated which asked that the British government posthumously apologize for prosecuting Turing for homosexuality. The petition was answered by Prime Minister Gordon Brown the next month calling what happened to Turing "appalling."
Alan Turing is a man who should have been considered a national here as much then as now. Yet 60 years ago, homophobia was so strong that even a gay person who had a large part to do with the salvation of his country was looked down upon and persecuted. At the very least, we can say that in 2002, Turing was considered one of the 100 greatest Britons (21st to be exact). Keep in mind also that if you are reading this on a computer (or pretty much any technological device), you probably have Alan Turing to thank for that.