Unkempt from a 12-week training camp, with half-beard and longer-than-usual crop of hair, Joshua proclaimed himself the No 1 in the division.

After a full 45-minute sweatshop workout at the English Institute of Sport, Sheffield, in front of the flashing cameras, sponsors, and PR gurus purveying his every move, Joshua dismissed the notion that any other had the right to claim himself as the leading heavyweight in the world.

The fist on the desk with a thud was a comment aimed roundly at Tyson Fury, who is scheduled to face the other belt holder, the unbeaten American Deontay Wilder, next, most likely in Las Vegas in early December.

Tyson Fury believes he is the top dog in heavyweight boxing © Getty Images Tyson Fury believes he is the top dog in heavyweight boxing Fury has trumpeted, since his return, that as the unbeaten fighter who beat Wladimir Klitschko, he remains the “lineal” heavyweight champion.

Joshua, 28, undefeated in 21 fights, scoffed at the words. “No. I am No 1,” he said. “Name me a fighter that has a better record than me after 22 fights [Povetkin will be his 22nd]. I ain’t got to show anything. History will tell you. History is all that matters. I will prove myself. Ever since the amateurs, non-stop I have been on top of my game.

“I was watching a Wladimir Klitschko fight the other day and he had time to learn. I’ve been in at the deep end time and again. If people aren’t satisfied with it now, they never will be. Look at Floyd Mayweather. They are never happy with him and he is one of the greatest of all time. They said the same of Lennox Lewis, now he is looked back on as a slick operator.”

Eddie Hearn, Joshua’s promoter, chipped in: “It’s nonsense to say Fury is still the lineal champion. The man who beat the man but then failed a drugs test and then went out for two years and has done nothing.”