In work that remained secret until long after the war, Turing is
credited with breaking the code used to encrypt communications
between German U-boats operating in the North Atlantic, sinking
merchant ships bringing much-needed supplies to the island
"Turing managed to break into the daily U-boat traffic and once
they were reading the messages, then they knew the positions of
the U-boats and the convoys could be routed around the U-boats,"
Copeland, who has written several books about Turing, told AFP.
Some historians have estimated that without this breakthrough, a
war claiming millions of lives every year might have continued
another year or two by allowing Hitler to entrench his position
In another incarnation, Turing developed a measure of artificial
intelligence that is still applied today -- the so-called Turing
Test which states that a machine would be truly intelligent if a
human could not differentiate between its response to a question
and that of another human.
And towards the end of his life, he published research on how
organisms develop certain patterns, like stripes on a zebra or
spots on a cow -- his most cited paper.
In spite of his achievements, Turing's name was not widely known
when he was alive.
He was said to have been shy but funny, "a very sort of geekish
mathematician", according to Barry Cooper, himself a
mathematician who heads the Turing centenary advisory committee.
He was also an excellent long-distance runner.
A hay-fever sufferer, Turing took to wearing a gas mask to
protect himself from pollen while cycling.
As a boy, he was described as an odd character, untidy and
scruffy, Cooper said.
He was made an Officer of the Most Excellent Order of the British
Empire after the war, the second lowest-ranked order, in a move
regarded as an insult by Turing fans today.
Three years ago, then-British prime minister Gordon Brown issued
a posthumous apology and said Turing had been treated "terribly."
Commemorative events are being planned this weekend in countries
including India, South Korea and the United States as well as at
the universities of Manchester and Cambridge in Britain, where
There will be a music concert in his honour in Seattle and a
tribute walk ending at Sackville Park in Manchester where a
life-size statue of Turing sits on a bench holding an apple.
"I don't think he could have imagined" his posthumous acclaim,
"I think he probably wouldn't have cared much, either.
"He was driven by curiosity and the spirit of scientific enquiry
and as long as he knew, he didn't much care about passing his
ideas on to other people."