"It is a question of the highest honor a nation can endow to a person posthumously. In Great Britain it is the Westminster Abbey."
Highest honor? Annual national public holiday for "Stephen Hawking day" would eclipse that any time. Years to come those apart from Darwin, Newton and perhaps Hawking - all those other scientists buried at Westminster are only footnotes whereas a Hawking Holiday would make him rather immortal.
Or perhaps erecting a statue at Trafalgar Square. Founding (ok, unlikely) or renaming cities. Or naming the killer Asteroid coming straight at us.