David Sinclair sits in his office at Harvard Medical School and we scrutinise each other via a video call. He is a youthful-looking 50 and believes that the pioneering work he and other human biologists are doing could help him to live for another 80 years.

I am also 50 and tell him that I find this very encouraging. Might I too live decades into my second century? “If we continue on this path, there’s a chance,” he says.

This is not quite the unambiguous prediction I had hoped for, but there is no doubt that Sinclair, an expert on ageing, has some extremely eye-catching things to say about how long we might live and what that means for the future of our species. He