"During the 2018 World Cup in Russia, it emerged that a seven-page document had been supplied to stadium security staff, detailing dozens of flags that tournament organisers had banned from being displayed. These included the flags of jihadist terrorist groups al-Qaeda and al-Shabaab, of pre-revolutionary Iran, and separatist emblems for Somaliland and Catalonia. Sandwiched between the flag of the Luhansk People’s Republic and the Catalan Estelada was flag No 29, a flag actively prohibited from being displayed at the biggest sporting event on the planet. The flag of Sealand. …”