Interesting to note that the Justice Minister Lord McNally didn't consider a pardon appropriate, but the Queen eventually pardoned Turing after an outpouring of public support (and with the advice of the Government) [0]. (Turing was convicted for committing homosexual acts. Based on my cursory reading it seems like it was one of the reasons why he likely committed suicide. It's a tragic story of a great man, whom we all owe our gratitude.)
[0]: https://en.wikipedia.org/wiki/Alan_Turing#Government_apology...