There seems to be a more quirky side to this, as he was chemically castrated and barred from working for GCHQ, and eventually driven to suicide for his sexuality. A certain Austrian, who ran a murderous political party next door (in Germany) would have loved that, had he been alive to see it. And now the scientist is on a £50 note - of which Mark Carney said would be no more...for its reputation rather than anything else.
And so - those who tend to use such notes - which will not be a great many of us - will not see the new ones 'until 2021'. And those who do will surely be the sort who would rather not 'pay what's due', make sure the Swiss bank will 'always be ready for business', or any other comical 'Only Fools and Horses'-lot who giggle at the taxman.
If there was any note that would be contaminated with cocaine and the like soon after entering circulation, this would surely be the one.
Poor Alan Turing...