It's not Alan Turing who needed pardoned
It was well-meaning. But David Cameron's tweet expressing gladness that Alan Turing had been awarded a Royal Pardon because, "he played a major role in saving this country," only reminded people of the injustice of criminalising people for being gay.
Turing was a genius whose pioneering work was curtailed when he was convicted and chemically castrated.
It's the law-makers who did this who should be begging for a pardon. Every gay person who was ever prosecuted due to their sexuality should receive a grovelling apology and compensation.