Unionistas, with their unlikely link to Bath, were initially dismissed as a pub team but their rise through the Spanish leagues has been dramatic

At one end of the Estadio Pistas del Helmántico in Salamanca, an unusual advertising banner is hung. 'Bath City Boat Trips', it reads, with an image of a passenger boat floating down the Avon. You do wonder how many football supporters in western Spain get persuaded to take a day tour on a river 900 miles away.

There can't be many more out-of-place adverts at a football stadium, or ones that provide fewer direct referrals. But the banner is placed there for a reason. After every Unionistas de Salamanca home game, it is taken down and kept in storage until the next home one. This isn't an advertorial; it's a symbol of loyalty, gratitude and dedication.

The short history of Unionistas de Salamanca is a story of triumph rising out of adversity. In 2013, UD Salamanca folded after 90 years as a professional club. Salamanca had spent three years in La Liga in the late-1990s, when Portugal striker Pauleta and Michel Salgado called the club home before moving on to bigger and better things. But times were hard.

By 2013, the club's debts amounted to 23m euros. A meeting of creditors failed to secure any agreement. The official supporters' group had put forward an economic package, but president - and businessman - Juan Jose Hidalgo, who had promised investment but delayed administration, wanted to liquidate and he had the ultimate power.

"Today is the saddest day in our history," a club statement read. "We are all in tears and will always be in your hearts."

Hidalgo's plan was to start again with no debt and change the name to Salamanca Athletic Club, but a group of supporters had made their own pact.

They would form a tribute club, a fan-owned entity created to preserve the memory of UDS. Unionistas would be a democracy in which all members (current count is over 2,800) would have a voice and a vote. All directors would be volunteers. Never again would they be let down by a president or sponsors.

Unionistas implemented different categories of membership, allowing supporters to pay less - and only have free access to a certain number of games - right through to the level of socio colaborador. Those at that level choose to pay more, with the extra money going towards the running of the club. Former Spain and Real Madrid manager Vicente del Bosque is a member. So too is Spanish actor and comedian Dani Rovira.

By September 2014, Unionistas were placed in the sixth tier by the Royal Spanish Football Federation and played their first official friendly match a day later.

Expectations were low, but at the end of their first season Unionistas had been promoted as champions. Twelve months later, they were champions again to reach the fourth tier. By May 2018, they were crowned champions in the Tercera Division to reach the third tier. In their first three campaigns, Unionistas lost only five league matches. They scored 257 goals, and conceded 65.

This season, they will finish in mid-table despite having one of the lowest budgets in the division, went on a 12-match unbeaten league run and competed in the Copa del Rey for the first time.

Salamanca Athletic, Hidalgo's club, never played an official match and were officially dissolved in 2016. Fan power won.

Two of Unionistas' socio colaboradores are Tony and Peter Murphy, two brothers originally from north Staffordshire. Peter emigrated to Salamanca in the 1980s to set up a language school, and being a football obsessive immediately purchased a UDS season ticket. He held it for 28 years, was present at the club's last game before liquidation and was outside the stadium when Hidalgo told supporters their club had died. He remembers the day with genuine sadness.

Tony runs Bath City Boat Trips, still lives in England and would visit Peter several times a year to follow UDS to home and away matches. They became friends with many of those who would form the tribute club. In the past five years, the two brothers have been integral in establishing an extraordinary fan culture.

Tony and Peter Murphy, bottom right, could one day be watching their team in La Liga

"In Spain, it's not normal to travel away to watch your team, but wherever we play we take a large following that never stops singing," Tony says. "In Zamora last season we took over every bar in the city before and after the game. This season Unionistas fans have been voted the best in the second division B, which comprises a total of 80 teams.

"In September I flew over to Vigo to watch our first ever game in the Copa del Rey. It was a midweek game with a late kick-off, hundreds of miles from Salamanca, but there were more visiting fans than home fans. And we won 4-0, which made it all worthwhile."

Regularly attending matches of a club based 900 miles away might not be normal, but nor too is Tony and Peter's commitment to Unionistas.

Both have given additional financial support to the club to help pay for extra wages and new signings to fund deals that the club would not otherwise have been able to afford.

Peter also subsidises away trips for many supporters by paying for coach travel. He is keen to stress that he has never sought recognition for doing so, but it makes him and Tony minor celebrities in Salamanca. Tony has now started taking his nephew to matches, and is hopeful of expanding a Unionistas supporters' club in England.

"It's an amazing feeling to be part of the Unionistas family," says Tony. "The statute of 'one member, one vote' means that every single decision has to be approved by a majority of the members. I vote electronically as I cannot attend every meeting personally. But every time I travel to Spain I get an incredible reception from the club. People must think I am a complete nutcase."

For them, Unionistas is the chance to be part of a football family, to have tangible ownership of something that is very dear to them in a sport they adore.

When a small group of supporters create a new team, everything is stacked against them. The plan was widely derided as a vanity project and Unionistas as a pub team. So much time and effort went into getting the club off the ground and, crucially, they have stayed true to their original ideals.

But it's also more personal than that. Unionistas allows Tony and Peter to continue the bond of watching football together in Salamanca that started more than 30 years ago when Peter emigrated. The financial investment was worth it for that alone. Now in their 60s, they cannot imagine a time when they stop. And if you see a man on a narrowboat in Bath wearing a black football club jacket, he's only too happy to tell you his story and the story of his new club.

"I know it's completely ridiculous, a bloke with a small business in Bath sponsoring a Spanish football club," Tony says. "And I know I will never get any return on my investment. But I think it's funny and I am proud of it.

"Did anyone see this coming? No, they laughed at us. But they're not laughing any more. This club's rise has been meteoric. This is what we have achieved, laid out in front of us for us all to see. Two more promotions and we would be playing Barcelona and Real Madrid. It's a far-fetched dream, I know that. But what's the point in not dreaming?"