Football fans returning from the Champions League final in Portugal have been told to self-isolate after multiple flights reported passengers testing positive for coronavirus.
Posting on one fan forum, passengers reported as many as five flights organised by Manchester City for the match against Chelsea have been affected.
It follows reports that Portugal will be removed from the green travel list on Thursday.
The summer hotspot is set to be placed on the amber list following a meeting between Westminster, the devolved governments and the Joint Biosecurity Centre, according to the BBC.
Dom Farrell, a sports journalist for Stats Perform, travelled to Porto for work and received a notification from NHS Test and Trace four days after flying home, telling him he needed to self-isolate for seven days.
He said a colleague on the same flight had received the same notification, leading him to believe that others onboard had too.
Mr Farrell said it was unnecessary for the match to take place abroad when two English clubs were competing.
He said: "If I'm being entirely honest, it shouldn't have happened. And I'm not saying that because I have to self-isolate.
"It just seems silly it wasn't happening in the UK."
Wembley was considered as an alternative venue for the fixture, but the UK Government could not accommodate the request to allow quarantine exemptions for thousands of sponsors, VIPs, and broadcasters.
Mr Farrell said: "City and Chelsea played five Champions League home games apiece this season to get to that game. I don't see why they couldn't have played the sixth in this country without all the dignitaries there.
"I'm all right – I can put my tests through expenses at work, but there will be people who were on that flight who will have paid for a ticket, paid for all their tests, and will now maybe be losing a week of work."
Andy Saunders, from St Albans, was told by his NHS Test and Trace app to self-isolate for 10 days after returning on a flight from Chelsea's "appointed travel partner" — a Tui flight, he said.
He said it was "frustrating" because he has tested negative since returning home, and has received his first and second Covid vaccination jabs.
To travel for the match, he had to take a PCR test the Thursday before flying out, complete a passenger locator form at both ends and provide evidence of a test two days after returning.
He told the PA news agency: "The mask-wearing from Chelsea fans [on the flight] was very compliant, and everyone behaved themselves. I think that makes it even more frustrating."
He said it was an unnecessary risk to hold the game in Portugal.
"It's absolutely ludicrous that it was held in Porto," he said.
"I live 35 minutes from Wembley, to make me get on the plane and fly over and expose me to those risks, which have clearly manifested themselves, is ridiculous."
However, he said he did not blame the clubs, adding: "It was purely a UK Government decision not to allow any kind of quarantine waiver for people coming in."
He also said he did not regret going and called it a "once in a lifetime opportunity".
"For a football fan, it's the absolute pinnacle," he said.
UEFA, Chelsea, Manchester City, Tui, Ryanair and Jet2 have all been contacted for comment.
