Steve Brown is talking to me from the summit of a hill near his home outside Aylesbury, sitting in his 4X4, the only place with a decent phone signal.

This doesn’t surprise me. After all this is a man who likes extremes in terms of terrain, career and experience, indeed what he positively thrives on.

Until he went to Afghanistan that is, to serve with the Grenadier Guards in 2012 as an advance team medic. The trauma of the tour and the horrific incidents and injuries he witnessed caused him to go “cuckoo” once it was over.

Picked up homeless by Veterans Aid in 2014 and diagnosed with post traumatic stress disorder, he was placed in a hostel in East London, and put in touch with Band Of Brothers, a Help For Heroes charity. They offered him a place on the Round Britain Challenge sailing trip, circumnavigating the UK on a 92ft schooner run by Turn To Starboard.

Gifted by The Prince’s Trust, Spirit of Falmouth set sail crewed entirely by similarly scarred UK military veterans from Iraq, Kosovo, Ireland and The Falklands. It is the subject of Steve’s resulting book Riddle Of The Waves, which he will be discussing at the Oxford Literary Festival on Wednesday.

“I’ve always had a little voice in the back of my head that said I should write a book, it’s just that most people don’t act on it, so I took notes and when we did the round Britain trip I put my hand up to write it.

“As Richard Branson said: ‘when an opportunity comes your way seize it and then work out how to do it afterwards’. But yes, I was cuffing it,” he says. “Because anyone who thinks that writing a book is easy or writes itself is wrong. That’s just not the case. You have to be focused and vigilant. So I had to be out of my PJs by 9.30am every morning and I wouldn’t stop until I’d written my daily word count.

“Some days were really difficult. It’s a proper job and an emotional journey.” Riddle of The Waves is not just about the expedition itself but also the individual stories of the crew members themselves. “The first part of the book was about the trip but after that I actually sat down with each crew member to discover the ins and outs of their story.”

Was he immune? “God, no. It really affected me. I took to tears and had to go and keep sitting in my car It was so overwhelming listening to these unsung heroes and the general bravery of your every day Joe Bloggs soldier in combat, who now have the strength to put up their hands and say they are struggling.”

“So while you have to accept the type of person who joins the military is looking for adventure and a challenge, I really wanted to capture their voices. It was so important to me. I’ve read so many army memoirs, and books like Andy McNab’s, and that’s not what I wanted Riddle Of The Waves to be about.

“Because this was a real mix of ranks, from lieutenant colonels to privates, from all different walks of life and upbringings, who all had the courage to ask for help, and I wanted to tell their stories regardless of their social groups.

“The irony was that they shared their individual pain, their specific Achilles’ heel, while sailing around the very island we had vowed to protect.”

Enormously therapeutic and practical, the comradeship aside, the trip enabled many to achieve their Yacht Master’s qualification and move on with their lives.

“Sadly there weren’t happy endings for everyone,” Steve confirmed. “Some are going through some pretty serious therapy and others are no longer with us, but everybody looked back on the project and had very positive things to say about it.

“There are lots of success stories, and it helped people move on, but it doesn’t fix everybody.”

As for Steve, the 49 year-old says: “The sea is so healing. And giving talks and spreading the word, has helped me to come to terms with my past, even though I still get choked up on stage sometimes.

“As far as I’m concerned you only get one crack at life so you need to pack it all in.

“I’m 50 this year, but still feel 25, and there is so much more to be done.”

Riddle Of the Waves

Steven Price Brown

Wednesday March 21 Weston Lecture Theatre

oxfordliteraryfestival.org