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Since his birth at the Royal Free Hospital, Hampstead, in October 2018, Harry Mattheson has doubled in size.

Yes. Actually doubled – from a modest 7lb to a beefy 14. If he keeps going at this rate, he’ll be a whopping 6 stone by his first birthday – that’s bigger than Richard Hammond!

Not content with a diet of sleeping and crying, Mattheson has been punching his fists in the air, doing three sets of ten headlifts to kick off every day, and working those glutes during floor time. He may not be able to walk or even crawl yet, but this little monster never skips leg day.

Existing on a steady diet of breast milk every two hours, he sleeps only four hours a night, choosing to supplement his energy with daytime power naps, like so many FTSE 500 CEOs before him.

Mattheson may sleep, but those muscles never do: this absolute machine has developed his patented ‘body rolls’, moving around the cot so he can feel the burn all night long. If Vin Diesel had started this early, who knows what he could have accomplished?

When asked about his success in tacking on mass, Mattheson was cagey as to what exactly is his secret. The body rolls? The instinct to grab at things? The sense of motivation when he is held up facing a mirror and can see himself? Mattheson didn’t tell – he offered a mysterious burble, and dribbled gormlessly on our reporter.

His father, Alan Mattheson, credits the milk: “I call it tit shake – it’s pure calcium. I’ve started mixing it into my NitroTech whey protein before circuit training, and offering it to other athletes as a supplement. My wife does NOT like that.’

Harry’s coach and mother, Aimee Mattheson, said, “I don’t know what to do. I keep thinking he’ll take a day of rest and recovery, but he’s unstoppable. My nipples are just two weeping sores at this point. I’m pretty sure he said “dumbbell” the other day…we might need to see a paediatrician.”

Harry’s story is told by Daisy Bard