I ran four marathons with a kidney infection. It was horrendous

threw up five times on the run and was weak as anything - and I ran four marathons with a kidney infection. I’d had food poisoning which led to extreme dehydration and my kidneys were not happy with it.

“While I was running in the Maldives it felt like I was being punched in the back constantly, which was horrendous.”

As for long term wear and tear, Nick is impressively blase about putting pressure on his joints. “By the time I’ll need new knees, you’ll probably be able to buy them in a supermarket,” he jokes. “I know people who have climbed Mount Everest with false knees, so I’m not worried at all.”

That’s not to say he has got off entirely scot free. “I had some torn fibres in my achilles in Prague which left with me with a lumpy ankle, but other than that I’m fine – I’ve done so much running in my life, it’s just standard.”

Along the way, Nick needed a rabies jab after a dog bit his backside in Tunisia, he’s also been mugged twice and saw a volcano erupt in Guatemala.

He has run a marathon around a small yard in the Vatican City, another on an airport runway in the South Pacific island nation Tuvalu and one in pitch darkness overnight in Syria.

“It’s surreal to think I’ve almost completed the challenge – but the stress seems to be mounting rather than dissipating,” he says. “It seems to be one of those weird paradoxes because there’s now a huge pressure to make sure I actually finish the the penultimate marathon – I’ll be running in Cape Verde as you read this – in order to do the final as planned this Sunday because so many people are flying out to Athens

INSPIRATION Nick with friend Kevin

to support me or run with me.”

As well as aiming to raise £250,000 for Prostate Cancer UK, Nick - who worked in banking, but quit five years ago - has used his challenge to raise awareness of the condition. His effort certainly seems to have paid off.

“Throughout my journey, nine people have emailed to tell me they had themselves checked and were diagnosed with prostate cancer as a result of having met me and had a conversation about the disease – none of them too late to be helped, which is quite powerful really.

“It’s awareness more than anything” he adds. “People have to realise we can’t be embarrassed about talking about prostate cancer any more because it’s killing people.”

As for what he has learned along the way, Nick says: “Kevin has taught me we shouldn’t wait for a diagnosis to change our lives. People always live for retirement and imagine they will go yachting in their sixties, but as Kevin told me, sometimes you don’t get there, so don’t wait to go and do what you want to.

“Running the world has been the most amazing experience.

“I never know what day of the week it is now, so I’m certainly not living for the weekend any more.”

■ To sponsor Nick go to justgiving.com/ fundraising/runningtheworld or visit runningtheworld196.com.

I told Kevin he had to live if I was going to do this, and he has. I really hope he’s going to be the miracle