The Danish report is in actually grams per seat km, both ASK and RPK. Taking the 777 figures at their worst, 36 g/ASK on a 202 seat aircraft means a burn of 7.27 kg/km. The Concorde figures of 175 g/ASK on a 100 seat aircraft means a burn of 17.5 kg/km, 2.4 times the 777 fuel burn.

For a confidence check, the BA site gives SSC's fuel capacity as 119,500 litres. Boeing's site quotes the 777-200's fuel capacity as 117,335 litres. And we do know that the 772 can go substantially longer than the SSC without refuelling ...

(Is there such a thing as a barrack-room mathematician?)