Justin Heath joined the Royal Navy because he wanted to “see the world” and “do something different”. But six years into his service, his career suddenly came to an end when he was diagnosed with a sleep condition which his superiors said would prevent him from ever gaining a promotion. The only option was medical discharge and a return to ‘civvy street’.

For the 31-year-old from Weymouth, this sudden change to his life’s plans came as a profound shock. “I was quite proud of my job and my role,” he says. “I’d joined up for the 22 years, and I’d go back tomorrow if I could. I wanted to get promoted and go through the ranks. Part of me thought ‘If I can’t do my job, then I can’t stay in,’ but the other half thought ‘What else am I going to do?’”

In the years after he left the Navy, his life became set on a slow downward spiral, a plight shared by many of the veterans being supported by The Independent’s Homeless Veterans Christmas Appeal. He found himself “floating around”, doing temporary agency jobs and working for charities in the South West of England. Recalling those years now, Mr Heath says he felt lost, aimless and confused – and eventually this led to him becoming homeless.

“I was living in between my car and a tent for two months,” he says. “The car wasn’t that comfortable, so I ended up mainly in the tent. I’d find a quiet little woodland, set up for a night and then move on. I wasn’t sure quite where I belonged or what I was supposed to be doing.”

He began to seriously consider living “off the grid”: selling his car, throwing away his mobile phone and heading for the countryside to “set up a semi-permanent camp as far away from civilisation as possible”. “That was the way I was going – it seemed like the only sensible option at the time.”

But in October this year, he was referred to Alabaré, the largest provider of dedicated accommodation for working age homeless veterans outside London. Since 2009 it has helped more than 250 ex-servicemen and women through its network of houses in Portsmouth, Plymouth, Weymouth, Bristol, Gloucester and Salisbury. It is now in the process of expanding into Wales.

The charity’s work is being supported by significant grants from ABF The Soldiers’ Charity, one of two organisations which will benefit from The Independent’s appeal. For Mr Heath, walking through the door of Alabaré’s house in Salisbury provided a “relief” from his previously nomadic lifestyle. “It was actually a bit odd sleeping in a normal bed,” he said.

Alabaré’s unofficial slogan is “homes, not hostels”, according to the charity’s campaigns director Geoffrey Willis. Its aim for veterans is to get them back to independent living within a year, so it has two tiers of accommodation: eight-bedroom properties for them to live when they arrive and smaller, four-bedroom “move on” houses that prepare them for living on their own.

“It’s about actually living in an environment which is close to what ultimately they’ll be living in, rather than part of a big institution,” he says. “If institutionalisation in the forces was one of the ingredients which combined to make it difficult for them to transition out, then we want to take them away from institutions and into homes.”

The charity’s newest home in the Gloucester suburb of Longlevens opened last month with the help of tens of thousands of pounds in grants from The Soldiers’ Charity. A pleasant and modern house on a quiet residential street, it does not look anything like a homeless hostel – yet according to Kenneth Kwogyenga, one of Alabaré’s housing support workers, some veterans arrive with little more than the clothes they are wearing.

“Once they open the door and step inside, they usually say ‘Wow!’, because when they are told they are going to be in a supported home, they think it’ll be a place which isn’t really looked after,” he adds.

Each room is kitted out with a welcome pack of towels and toiletries. Eating is a communal activity, with residents contributing money for the items on a shopping list before taking turns to make an evening meal for everyone in the house.

“The main thing is camaraderie. We want to eliminate the process of people being alone or feeling lonely, we want them to feel part of a family. The good thing is that because they’ve all served in the forces, that communality comes in,” says Mr Kwogyenga, who is himself a veteran, having joined the Army in 2007 and served with the Royal Electrical and Mechanical Engineers for six years, including in Afghanistan.

Particular attention is paid to ensuring that each veterans’ house has communal space, so the residents are encouraged to socialise. Alabaré even spent £10,000 on improving a property in Plymouth, knocking down internal walls to open up the central living area. “One reason it works is that they’re able to support one another,” says Mr Willis.

For Mr Heath, being around other veterans helped him settle in quickly. “There’s always a kind of unwritten bond between ex-military, regardless of where you served or how long you served,” he says. “You automatically just get on with the guys. It’s nice because you know you fit in and you feel safe.”

Once the residents are settled, a team of specialist support workers are brought in to help each veteran decide on their next step. According to Mike Hibberd, care and support manager for veterans services at Alabaré, each individual may have a totally different reason for being there.

“Somebody may come in and they may have become homeless due to relationship breakdown, it might be that somebody has issues with addiction, it may be that somebody’s business has collapsed,” he says. “Anybody can fall upon hard times and experience homelessness – it’s no different with those who have served in the Armed Forces.”

One of the residents of the Gloucester house is Roger Laughlin, 69, from Ilfracombe in Devon. He joined the Army in 1962 at the age of 17 and served for 12 years, including in Northern Ireland, followed by 16 years in the TA.

Two years ago he and his wife moved to Spain, but the house they bought turned out to have been built illegally. The stress of losing their home and their life savings took its toll on their marriage and they have since separated. With nowhere else to go, Mr Laughlin returned to the UK and was helped by Alabaré.

If he had not been offered a place in the Gloucester house, he adds, he would have “probably been on some park bench” in a public gardens. “I didn’t expect it to be this good, to be quite frank,” he says. “I thought it might have been similar to the YMCA, but it’s like Buckingham Palace.”