“I put my Army hat on,” he said. “I returned to it.”
Following service around the world, including in the first Gulf War, it took losing his job of three years at a small electrical firm in Skipton to sow the seeds of his homelessness.
“It was largely down to the fact that I lost my job and my wife lost hers. We had savings, we had money, that was not a concern or worry, but then the arguments started.
“It was the same argument day, after day, after day, after day. For my own peace of mind I had to leave.”
Originally from Bangor in Northern Ireland, from a young age Mr Lucas was in the Royal Corps of Signals – which provides battlefield communications and information – and was “based everywhere”.
That included Malaysia, Hong Kong, Cyprus, Belize, Germany, the Gulf War, Ireland and Washington.
He said: “I did what they wanted me to do; I put my hand up.”
Despite his years of service as a signalman and in other areas, Mr Lucas turned to the streets around seven years ago after the break-up.
Although he witnessed sights “there’s no way you could publish”, Mr Lucas himself never experienced violence on the streets, but retreated into corners to escape into the world of Bernard Cornwell’s Sharpe novels, or anything else which inspired his interest in history – a subject he has a degree in.
He said: “I kept myself to myself, I was not looking for trouble and I didn’t find any.
“I’m a great reader, I would get books from the library, I would read anything.”
Meanwhile, continuing with his Army mindset and turning up on time to any necessary meetings during his six weeks of homelessness – “I found resorting back to that has always happened with me” – he was referred to Emmaus after others on the streets had mentioned it to him.
The charity was set up in France following the Second World War by Abbé Pierre, a man who Emmaus regional communications officer Andy Fowler describes as “maverick resistance fighter-come-priest-come-politician”.
It came to the UK in 1991, and the Leeds branch is now one of many around the world helping homeless people to re-build their lives through work and shelter.
The facility in St Mary’s Street off Mabgate runs a large second-hand shop staffed by people who have been homeless and live at the site’s supported living quarters, which caters for up to 26 people.
Proceeds from the store – which stocks furniture, white goods, bicycles, and much more – go back into running the service.
Mr Lucas left Emmaus five years ago after he started living there in 2011.
He said: “I came down for my interview. I was lucky enough that within three days, I got a room here. I started work the next day and that was me here for the next two years.”
New staff initially try out a range of roles, including shop, warehouse and delivery work, but Mr Lucas surprised himself with a knack for sales and ended up running the charity’s stall at Kirkgate Market.
He said: “It was something to get up for and get my teeth into. I was not sitting around brooding. I looked at it as a stepping stone.”
Then he met a new partner, Fiona, and decided that it was time to leave the charity to move in with her after they dated for five months.
Sadly, their time with each other was short-lived.
“We had two great years together, and unfortunately she had terminal cancer. She died in 2016,” Mr Lucas said.
“It was a kick in the teeth, and that’s me being polite. If it hadn’t been for my friends at work, and work in general, that would have been a really dark time.”
Mr Lucas is now a floor manager at Aldi in Seacroft, close to where he lives in Swarcliffe, and his colleagues have helped him to keep his spirits up.
“They rallied around. They were amazing. I was not expecting it, it was absolutely fantastic. They gave as much support as they could.
“It’s still hard, even now, to think about her. But it’s one of those things. I’ve tried to move on as best I can.”
In his spare time, he enjoys playing golf and watching the Leeds Rhinos with friends.
He said: “I’m never going to be a multi-millionaire, but I’m happy, I suppose.”
Speaking about Emmaus, he added: “For me it was extremely vital. It was a base to re-build and it was just what I needed at the time.
“It gave me a purpose.
“Don’t judge a book by it’s cover. Don’t judge Emmaus by its cover, come in and take a look.
“Everyone from fallen millionaires to people on their way up will have hit a brick wall. Don’t be afraid to come in and speak to people.”