In a letter to The Daily Telegraph, Stephen Hawking and others called Turing "one of the most brilliant mathematicians of the modern era."
"Yet successive governments seem incapable of forgiving his conviction for the then crime of being a homosexual," the letter says. "We urge the prime minister to exercise his authority and formally forgive the iconic British hero."
Turing was a pioneering computer scientist who led the effort that broke the German Enigma code. He took his own life in 1954 at 42, two years after he was convicted of homosexuality and forced into hormone treatments as an alternative to imprisonment.
The letter was also signed by Martin Rees or Baron Rees, the astronomer royal, Sir Paul Nurse, head of the Royal Society, and Jean Barker, Baroness Trumpington, a Conservative politician who worked with Turing during the war.
Former Prime Minister Gordon Brown apologized for Turing's treatment in 2009. In February, Justice Minister Tom McNally rejected a bid to pardon Turing, saying he was legally convicted, albeit under a law that now seems "shocking."
A columnist for The Guardian suggested pardoning Turing and other well-known people who ran afoul of the law against homosexuality would do nothing for them while overlooking the ordinary people who were also convicted and punished.