Football fans heading to Russia for the World Cup should be wary of hotel and public wi-fi and keep their devices with them at all times, cyber security chiefs have warned.
The National Cyber Security Centre (NCSC), a branch of Government listening post GCHQ, said fans should think carefully about how to secure their personal data and issued advice.
Fears over the Russian government's internet capabilities have been heightened in recent months in the wake of the Salisbury spy poisoning, with the Director-General of MI5, Andrew Parker, warning on Monday of the Kremlin's "high levels of cyber attacks".
And the risks to individuals' personal data have come into sharp focus following the Facebook and Cambridge Analytica scandal.
The NCSC, in a blog post entitled "Avoid scoring a cyber security own goal this summer", recommended fans check with their mobile network whether their phone will work abroad and consider taking only what is necessary.
It suggested: "It may be safer and cheaper to buy a pay-as-you-go phone."
Antivirus software and all apps on any phones, tablet or laptop should be up-to-date and data should be backed up before leaving for the tournament.
The ability to wipe a phone of data should it become lost should be turned on and all devices should be password-protected, with two-step authentication enabled on important social media and email accounts.
The NCSC urged fans to avoid streaming or downloading content from unofficial sites and advised against using internet banking while abroad, as well as plugging in any USB sticks offered as gifts.
The blog also said: "Public and hotel wi-fi connections may not be safe; carefully consider what information you might be sharing when using these connections.
"Stay alert when using devices and don't share your phone, laptop or USBs with anyone.
"Keep your devices with you at all times if possible rather than leave them unattended. Hotel rooms, safes and lockers are not always secure because other people may have access codes or keys."
More advice is offered on the Foreign Office's travel advice and Be On The Ball web pages.