I was looking at some Concorde pictures today and just remembered the good old times of great promotions.

A few years ago, BA used to have this 50,000 miles promotion for any Club Europe flight (and 100,000 for Long-haul). All it took was to fly CDG-LHR in Club for 380 € return (my company's rate at the time), and you'd get 50K. And a LHR-JFK flight beeing , with the 20% miles discount, only 48,000 miles at some time of the year (5 or 6 months a year), it was easy to get a one way flight to NY on Concorde for under £250 tax included. And the availability was never a problem.
And for the same £250, you could also fly return in business ... (the 20% discount was not offered out of the USA if I remember correctly).