As Barcelona have eight players who won the World Cup with Spain this summer, a celebration was planned for Thursday night on the Camp Nou pitch.That number would have been higher had Ferran Torres — who scored the winning goal in the final against Argentina on July 19 — not left for Paris Saint-Germain earlier this month, but the Catalans still have Lamine Yamal, Pedri, Gavi, Eric Garcia, Joan Garcia, Dani Olmo, Pau Cubarsi and new signing Rodri.The plan, arranged with the Spanish football federation (RFEF), was for these players to pose with the World Cup trophy before kick-off against Athletic Club in Barca’s first home match of the new La Liga season. Other clubs around the country had done the same — including at Real Madrid on Wednesday night.Mikel Oyarzabal and Marc Cucurella at the Bernabeu this week (Denis Doyle/Getty Images)But Barcelona cancelled it. To understand why, we need to rewind to last Sunday and an incident before their season opener at Elche.A short video shared on social media that day showed police officers confronting a Barcelona supporter queuing to get into the ground before kick-off. The officer went over to him and grabbed his Estelada flag — a symbol of the Catalan independence movement.In the video, the Barcelona fan — who authorities later confirmed was 17 years old and therefore a minor under Spanish law — was then dragged out of the queue. The police officer and other colleagues struck him with truncheons, and he physically retaliated, throwing punches towards the officers before he was knocked to the ground and held there.The supporter was arrested and has been charged with assaulting a police officer. If the case proceeds, it will be heard by a juvenile court and, as a minor, he would almost certainly not face jail time were he to be found guilty. Judges tend to favour rehabilitation measures such as community service in such instances.The following day, Barca’s president Joan Laporta called the fan and his family and offered to provide legal support via the club, which has now been arranged.Barcelona also issued a statement that read: “The club considers that the procedure for detaining one of our supporters was disproportionate and lacked the necessary proportionality and appropriateness in the use of force.“Likewise, FC Barcelona regrets that, once again, police officers confiscated Estelada flags from Barca supporters. The Estelada is a legal symbol and its display constitutes a legitimate exercise of freedom of expression and cannot, in itself, be considered an incitement to hatred or violence.”The ‘Estelada’ is not a banned symbol in Spain and football fans are permitted to bring the flag into stadiums. It is not classified by the police as a symbol that incites hatred, although it may be confiscated if the police perceive it is being used to provoke.The case also attracted comment from further afield. The president of Catalonia’s regional parliament, Josep Rull, sent a letter to the Spanish government’s minister of the interior, Fernando Grande-Marlaska, asking him to clarify the reasons behind the police officers’ actions and who had ordered it, describing the use of force as “disproportionate”.Omnium Cultural (a group founded to defend Catalonia’s language, culture and identity) and the Catalan National Assembly (ANC, a pro-independence organisation) called on their members to fill the Camp Nou with Estelada flags for the match against Athletic Club on Thursday. The ANC handed out 10,000 of them before the game and a demonstration was held outside the ground before kick-off.Fans unfurl an Estelada flag outside the Camp Nou (Kike Rincon/Europa Press via Getty Images)Meanwhile, Accio Cassandra, a group of lawyers actively seeking to defend “the Catalan nation in the European judicial sphere”, said they have filed a formal complaint against the police officers’ actions in an Elche court.On Tuesday, Spain’s Unified Police Union issued a video statement in which an unnamed spokesperson said: “This individual was not stopped for walking around with a flag; he was intervened against because he was using that symbol as an excuse to provoke, sow hatred and shout racist chants.“His reaction when asked for his ID was to assault one officer and then another. Far from behaving reasonably upon being arrested, he continued, whilst on the ground, to kick, spit at and hurl appalling insults at the officers’ families.”On Wednesday, Laporta told Barcelona’s in-house media that going ahead with the World Cup tribute would not be “appropriate”. Club sources, speaking anonymously as they did not have permission to comment, said they did not wish to expose the players to a political demonstration.At Athletic Club’s San Mames ground in Bilbao before their season opener on August 22, the team’s three Spain players at the World Cup — goalkeeper Unai Simon, Aymeric Laporte and Nico Williams — went through a similar presentation to the sound of boos from the crowd. Athletic’s support has long carried a large degree of aversion towards the Spanish national team, related to support for Basque separatism in the region.In the end, the pre-match before Barca’s game against Athletic passed without incident or drama. There were perhaps a few more Estelada flags in the crowd than usual.“We hope that all this will finally enable Culers (a nickname for Barca fans) and Catalans to carry the Estelada without putting our physical safety at risk,” Laporta said in the same remarks on Wednesday.“I hope that the Estelada will no longer be stigmatised by the state’s security and law enforcement forces.”