As Celtic appeared in Spain this month to play Athletic Madrid, crowds of fans in the away end could be seen waved defiantly waving Palestinian flags.
The Scottish football club has long been associated with fervent opposition to Israel, and this animosity has reached new heights since Hamas attacked the Jewish state on October 7, but why does the club have an affinity with the Palestine cause?
Celtic supporters show their support with Palestine flags during the Cinch Scottish Premiership match between Heart of Midlothian and Celtic FC at Tynecastle Park on October 22, 2023 in Edinburgh, Scotland. (Photo by Ian MacNicol/Getty Images)
During games immediately following the terror group's invasion, supporters brandished banners reading "Free Palestine" and "Victory to the Resistance".
In response, Celtic banned the Green Brigade - a hardcore group of fans seated in one corner of the stadium who lead protests, chants, and flag displays – from home matches.
It might seem incongruent that supporters of a Scottish Premiership team would rally passionately against the state of Israel, which is some 4,000km from Glasgow.
The recent spat, however, is just the latest in a long history of Celtic support for the Palestinian cause.
The club, founded by Irish Catholic immigrants in 1887, forms one-half of the Old Firm alongside their traditionally right-wing city rivals, Rangers. Between them, the pair have won all but a handful of Scottish League titles.
'End Zionism': Celtic fans protest for Palestine during the 2018 Scottish Cup Final (Photo by Mark Runnacles/Getty Images)
As Rangers fanbase is overwhelmingly Protestant, the footballing rivalry with Celtic overlies a deeper sectarian division that has occasionally erupted into religious violence.
Celtic has also long been associated with support for Irish nationalism, which has intertwined with the backing of left-wing social movements.
People walk past a pro-Palestinian mural on the Republican Falls Road in Belfast on October 23, 2023. Northern Ireland may be thousands of miles from the Middle East but signs of the current heightened conflict can be seen on the streets of the capital. (Photo by Paul Faith / AFP) (Photo by PAUL FAITH/AFP via Getty Images)
In the late 2000s, Celtic fans began waving Palestinian flags and in a knee-jerk response Rangers supporters began to display Israeli flags.
At the forefront of this solidarity were The Green Brigades, who have also demonstrated against the club putting poppies on players' shirts for Remembrance Day, supported Black Lives Matter, and branded the Scottish Conservative leader and part-time referee Douglas Ross a "c***".
In 2016, the Brigade raised £130,000 in an online campaign for medical aid for Palestinians and to create a football academy in Bethlehem.
In a recent statement, Celtic said they had now suspended the tickets of Green Brigade fans over their "repeated incidents of unacceptable conduct".
Responding to the ban, the ultra group said: "Despite disingenuous claims, we have absolutely no doubt that these sanctions are motivated by a desire to quash political expression within the Celtic support, specifically in relation to Palestine at this time.
"In spite of this, and any further obstruction, we once again encourage fans to courageously fly the flag for Palestine.”
Speaking to the JC, one Jewish Celtic fan who has been attending games for 30 years, said that some supporters from the community are "definitely questioning" their relationship to the club after seeing banners expressing resistance.
The man, who did not wish to be named, said: "It’s not that they feel unsafe. It's not a hotbed of antisemitism."
Green Brigade members, he added, would claim not to support Hamas if asked.
The Palestinian flag is carried outside the ground prior to the UEFA Champions League Play-off First leg match between Celtic and Hapoel Be'er-Sheva at Celtic Park on August 17, 2016 in Glasgow, Scotland. (Photo by Steve Welsh/Getty Images)
"I suspect deep down they know they got [banners supporting the 'Palestinian resistance'] wrong.
"They are probably not what you think they are. They’re all sort of Marxist intellectuals who spend time in Marxist reading circles. They’re definitely not thugs, not football hooligans."
He added: "If they meet a Jew one on one they’re not going to treat them any differently.
"They've got a blind spot, they see [Palestine activism] as punching up rather than punching down. They believe all the settler-colonial stuff about Israel."
Celtic Football Club fans show their support on Westminster Bridge. Tens of thousands of people marched in central London in solidarity with Palestine as the Israel-Hamas war intensifies. (Credit Image: Vuk Valcic/ZUMA Press Wire)
Despite the anti-Israel hostility, he said, there are probably still more Jews in Glasgow supporting Celtic than Rangers.
Far-right fans of Rangers - some of whom recently flew a Nazi Totenkopf flag - are more "scary" for the Scottish Jewish community, he claimed.
Jewish leaders have meanwhile called for displays of both Palestinian and Israeli flags to end.
Speaking to the JTA last year, Paul Edlin of the Glasgow Jewish Representative Council said: “We want to see it stopped... The clubs don’t like it, but they won’t stop it from happening.
“There is no reason to fly the flags of countries at football matches for any reason — neither Israeli nor Palestinian."
In a statement, Celtic said: “Celtic is a football club and not a political organisation. One of our core values from inception is to be open to all regardless of race, colour, politics or creed.
“That is why the club has always made clear that political messages and banners are not welcome at Celtic Park, or any match involving Celtic.
“At a time of loss and suffering for many, it is entirely inappropriate for any group of individuals to use Celtic Park as a vehicle for such messages.
“We call on all supporters, regardless of their personal views, to unite in backing our players and the club while respecting the rights and beliefs of others; particularly those whose lives are affected by violence and hatred.”