In Palacio Ibaigane, the regal building in Bilbao that serves as Athletic Club’s headquarters, where the contracts were once signed, there hangs a pennant. It is in an office where Howard Kendall once entertained dignitaries over a drink.

The pennant commemorates the curious bond between the Basque club and Newcastle United, a friendship forged over 30 years ago and one that will be rekindled at Champions League level for the first time when the teams meet this week.

It all began in 1994, so the story goes, when an Athletic Club supporter missed their transport back to Bilbao and found themselves stuck in Newcastle following a UEFA Cup tie. “This is the story that is passed down,” Adam Stoker tells Sky Sports.

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“They were put up by a family here and the story got back to Bilbao about the hospitality from our supporters. That is why there was so much warmth for the return leg.” So started one of the more random but inspiring club connections in European football.

Back in Bilbao for the second leg, Athletic edged out Newcastle by the odd goal to progress on away goals, the home supporters invading the pitch and racing over towards the travelling fans upon the final whistle. Not to fight them but to applaud them.

For Stoker, of Wor Flags, the fan group responsible for the spectacular banners at St James’ Park, the story still resonates. “The people I know who were there just say that you cannot compare it to any football game you have ever been to before,” he says.

“They say that it was the best experience ever. The people did not spend a penny but had their drinks bought for them. The local hospitality was so warm. The scenes of people in the streets, no tribalism, just different cultures getting on, it was great.

“It is quite rare to have a relationship like this with an opposing team in football. Athletic was one that we were excited about [when the draw was made] because of that shared history. The only disappointment is that we do not get a trip over there as well.”

The first game that Stoker ever attended was Rob Lee’s testimonial in 2001, for which Athletic were chosen as the opposition because of that connection from 1994. When the clubs met again in a pre-season friendly in 2022, the bond was further cemented.

Athletic presented Newcastle with a flag symbolising the friendship. “Their captain Iker Muniain presented the flag to me on the pitch,” recalls Stoker. “It hangs at St James’ every single game. It is just next to the halfway line so it is visible on TV all the time.”

Julen Izagirre Garnika worked with Stoker to make that happen. The pair first connected when Stoker was writing about the club’s famous fans overseas and there are few more passionate than Izagirre. The Bilbao native fell in love with the Magpies 18 years ago.

“It all started with one player, Alan Smith,” he tells Sky Sports. “He represented the values that I loved. He was talented but most importantly he was a warrior, fighting all the time. I loved the players, the strip, the badge, the beautiful stadium, the culture.”

Since then, he has visited St James’ Park on seven occasions, often making the trip from Bilbao alone. “I even had an away day at Watford.” He was also too young to attend the legendary UEFA Cup game in 1994, but has heard tales from the Bilbao perspective.

“People in Bilbao still tell stories about that day, the older ones tell me how special it was. That the fans got on so well was the cherry on top.” Not that Izagirre was surprised. The supporters share a passion. “It’s a religion there and it is a religion in Bilbao too.”

Athletic remains his first love. “My grandad is the oldest season-ticket holder for Athletic. We are so proud of him. I think Athletic is the most special club in the world, unique in modern football. I think all true football fans have a soft spot for Athletic.”

That is a reference to the club’s famous cantera policy that means they select only players with a connection to the Basque region. Perhaps that resonates particularly with Newcastle supporters? “I think the areas are quite similar,” agrees Izagirre.

“I am born and raised in Bilbao and 99 per cent of the population support Athletic. Unfortunately, in other cities the local team are losing supporters to the famous teams. That does not happen in Bilbao because this is a unique club, with a special bond.”

Newcastle is a one-club city too. “Bilbao and Newcastle are countries by themselves, that feeling of pride, of belonging. The Basques and the Geordies are so similar. We are brothers from different countries. No other club in the world has a passion like us.”

Naturally, Stoker agrees. “There is definitely a crossover in terms of the passion, the strong sense of regional identity.” The plan is for those shared principles to be celebrated ahead of the Champions League game between the clubs on Wednesday.

A flag is being prepared to be presented to Athletic. “It is a favour we are looking to pay back this week. It is just to symbolise the connection between the two groups of supporters. It started over 30 years ago but that warmth is still there,” says Stoker.