Football fans risk losing thousands of pounds if they book illegal package holidays to attend European finals, the aviation regulator has warned.
Supporters could be targeted by unscrupulous travel agents offering fake or unlawful deals, according to the Civil Aviation Authority (CAA).
Arsenal play Chelsea at the Europa League final in Baku on May 29 while Liverpool face Tottenham in the Champions League final in Madrid three days later.
Prices for flights and accommodation soared after the teams secured their places in the finals.
Charter flights to Madrid are available for around £700 return and hotel rooms in the Spanish capital on the night of the game generally cost more than £1,000.
Return flights from London to Baku are priced at nearly £1,000.
The price hikes have left tens of thousands of fans scrambling to find the cheapest options.
European law means trips sold as a package – such as flights and accommodation – must be financially protected.
In the UK, the Atol scheme ensures consumers are given their money back or brought home when a company goes bust.
Andy Cohen, head of Atol at the CAA, said: “The dedication and support of football fans is without question.
“As some of the most passionate fans in the world, seeing four English teams in the European finals make these matches a once-in-a-lifetime opportunity for some.
“If fortunate enough to get a ticket, it is essential that travellers check for financial protection before booking their trips.
“Using a reputable travel company is essential but, above and beyond this, it is vitally important that your travel company offers Atol financial protection when booking as a package.”
Figures released earlier this month revealed that holidaymakers were fleeced out of more than £7 million by fraudsters last year.
The amount of money stolen represents an increase from £6.7 million in 2017, fraud reporting centre Action Fraud said.
More than half (53%) of the crimes related to the sale of airline tickets, with scammers particularly targeting people visiting family and friends in Africa and the Indian subcontinent.
One in four cases involve accommodation, such as payments to stay in upmarket villas which are either fictitious or are being offered without the owner’s knowledge. Spain and France are among the destinations most commonly affected by this issue.