Warburton wanted to return to playing, to prove the doubters wrong, but decided he did not want to be a player who was “just hanging on”

One day this summer Sam Warburton finished his day’s training and picked up his daughter Anna from nursery.

Anna recently turned two and it was time for some fun on the trampoline in the back garden. “She loves playing on there,” Warburton says.

Except there was a problem.

“I went to go on the trampoline but I couldn’t,” he says. “I just couldn’t balance on there. My knees were just too sore. I was like, ‘Flippin’ heck, that has never happened before.’ It was quite upsetting.”

Warburton led the Lions to a series victory over Australia and a series draw with New Zealand DAVID GRAY/REUTERS

One can imagine. You would think that was the moment when Warburton recognised that his rugby career was over, but it was not. It was merely another warning sign.

You see, Warburton had made a pledge earlier this year