Brits heading to Spain for the Champions League have been warned to take their passports or face being detained by Spanish police.
The Foreign Office has released some official advice for football fans who'll be travelling across the Channel to catch the Atletico Madrid vs Liverpool FC match on February 18.
Of primary importance is to remember your passport, as you're legally required to present it if requested by a police officer.
A driver's licence won't do – only the original passport or a clear photocopy, although police have the right to accompany foreigners back to their accommodation and request to see the original.
Spanish police routinely conduct passport sweeps of public events to locate criminals or people in the country illegally.
If an unruly Brit refuses to co-operate, they could find themselves in a holding cell.
"The police have the right to hold you at a police station until your identity is confirmed," the Foreign Office warns.
"Always take care of your passport, as obtaining a replacement is costly and time-consuming. Remember to keep a photocopy or scanned copy of your passport somewhere safe."
Brits are also reminded to keep an extra watchful eye on their possessions at airports, train stations and on public transport to avoid having their bag snatched by pickpockets.
That's also why it's vital to keep a copy of your passport somewhere safe, as this is the first thing an enterprising thief will pinch if they get the chance, along with cash.
If a supposed officer asks for your wallet instead of just your passport, be wary - they could be a pickpocket posing as a cop, targeting tourists in town for a big event.
"If this happens to you, establish that the officers are genuine and if necessary show some other form of ID," the Foreign Office advises.
"Genuine police officers don't ask to see wallets or purses."
Other tips ahead of the match include "follow Spanish police instructions and avoid physical contact of any type", including requests for photos or selfies.
Fans are reminded not to show up at Wanda Metropolitano Stadium obviously drunk or wearing any racist insignia or holding banners with political slogans.
They're also being told to expect to be kept behind for 20 to 30 minutes after the game to allow Spanish home fans to disperse, minimising the risk of scraps.
Don't drink alcohol on the streets of Madrid or the metro as it's illegal, as is letting off flares.