内容摘要：But Shelton was far from done and after the duo exchanged breaks early in the third set, the 22-year-old from Atlanta saved a break point for a big hold at 4-4.

But Shelton was far from done and after the duo exchanged breaks early in the third set, the 22-year-old from Atlanta saved a break point for a big hold at 4-4.

But that was his final major outing. "I knew I only had a certain timeframe for me to carry on doing it in my Speedos. You can't be doing it when you're 80."And despite their similar taste in underwear, Speedo Mick is not Superman.

The gruelling challenges took their toll, having "a massive detrimental effect on my mental health and my personal relationships", Cullen admits.Every mission has been followed by "a big comedown", he says. "After the last one, I hit the ground at 1,000mph and I ended up in a clinic because I had a big breakdown."Looking back now, I wasn't managing myself. It feels like I paid a massive price by doing all that stuff. It was too much for me. It was all too much."

The stage show, which opens at Liverpool's Royal Court theatre on Tuesday, has given Cullen a new focus.On the surface, it is about a "total hero" who "took on lots of big life-affirming tasks and completed them and raised lots and lots of money", says Boff Whalley, formerly of rock group Chumbawamba, who has written the music.

"But the real story is why he wanted to do that, and at what cost was he doing that.

"It's saying, 'He's like you, he's got problems and he's struggled with addictions and mental health problems, and this was his way of finding a way through those'."A UK start-up also keen to compete in this space is Nukoko. Two of its founders previously ran a real chocolate business and teamed up with a food scientist to form their new venture.

"We saw first-hand the issues with the chocolate supply chain," says Ross Newton, co-founder. Like Foreverland and Planet A Foods, Nukoko has opted for a key ingredient that the firm can source and process locally – to reduce food miles and insulate against supply chain risks. But in Nukoko's case the raw material of choice is not carob or sunflower seeds but fava beans."There's around a million tonnes harvested in the UK every year," says Mr Newton.

It's early days for the company but he adds that he hopes to begin selling their cocoa powder alternative to food firms later this year.Mr Newton says imitating the flavour of real chocolate is very hard but that, out of 25 crucial flavour compounds in real chocolate, his company's product manages to include 24 of them – though in some cases at slightly different concentrations.