A former British paratrooper who set off on a mission to walk around the coast of the UK with just £10 in his pocket and a vague plan (to keep the sea to his left) has completed a year of hiking and estimates he is around a third of the way through his journey.

Chris Lewis, 38, from Swansea in south Wales, decided to walk around the UK coastline after leaving the Parachute regiment and finding himself homeless and struggling to cope on “civvy street”. He slept on the street and in cars before being helped by the armed forces charity, Ssafa, but when he faced homelessness again decided to head off.

The adventure began on Llangennith beach on the Gower peninsula near his home city in August last year. Since then he has battled through storms and fierce heat, acquired a dog called Jet and suffered an ankle injury on a remote stretch of Scottish coast that left him struggling to walk and suffering the possibility of starvation until he fashioned a crutch and hobbled to safety.

Chris Lewis with his dog Jet. Photograph: Mark Broomfield

Lewis has fished and foraged, his military training coming in handy, and camped night after night, but has also been moved by the kindness of strangers who have fed and watered him. He has raised thousands of pounds for Ssafa and is hoping to reach his target of £100,000 by the end of his journey, whenever that might be.

“I set off with a couple of days of supplies and a tenner in my pocket,” said Lewis. “I have been truly overwhelmed by the amount of people that have gone out of their way to help me. Everywhere I go I’m offered beds, hot meals, food for Jet, baths, equipment, endless cups of tea and I’m never short of a drink in the pub.”

Lewis spoke to the Guardian as he sheltered in a barn from a squall on the island of Islay, the southernmost of the Inner Hebrides islands, off the west coast of Scotland. He had just dined on crabs he had boiled up with a bit of garlic.

“I’m looking out to the Atlantic with mountains all around me,” he said. “There’s a couple of eagles circling. It’s beautiful, wonderful.”

Chris set off with a tenner in his pocket. Photograph: Facebook

Lewis said that when he left the Paras, he did not feel equipped with life skills such as dealing with bills, letters and debt. “I was just pretty lost, I didn’t know where to turn. The army doesn’t teach you those little life skills.”

So he set off with no real plan. “I took the approach that I would take one day at a time and simply keep the sea to my left.”

Lewis picked up Jet, a former working dog in need of a new human companion, six months ago and they have been inseparable since. He also found a message in a bottle – which had been dropped in the sea by a boy from Northern Ireland more than 20 years ago.

He took the ferry over to Northern Ireland, returned the bottle and – while he was there – walked the Northern Ireland coast.

The toughest place so far has been the island of Skye, not because of the terrain but due to the searing heat during that leg. “The burns dried up and I had to carry the dog. We had a really rough time there. That sort of experience could faze you. But you have to embrace it. The hard parts are the most beautiful. I just get my head down and get on with it.”

Chris says he has been ‘truly overwhelmed’ by the support he has received. Photograph: Facebook

He has honed the survival skills he learned in the army but what he is really taking away from the journey is the experience with people he meets.

“People have been phenomenal. They have really egged me on. I was a very secluded man, I kept myself to myself. I had, to some extent, lost my faith in humanity but I’ve learned so much about people and how lovely they are. I feel I am back to myself.”

It is hard to estimate how far Lewis has walked and how far he has to go. Just how long the UK coastline is – taking into account islands – is a moot point. A blog on the Ordnance Survey website puts the coast of England, Wales and Scotland – plus islands - at 11,023 miles.

But the whole thing is complicated by tidelines, the number of islands taken into account – and does not include the Northern Ireland coastline.

“It’s not easy to work out,” said Lewis, not that he has tried. He still has plenty of time to decide what he will do next but can’t imagine going back to an ordinary non-walking life. “I think I’ll want to keep walking,” he said.