THOUSANDS of football fans travelling to the World Cup in Russia, and millions of holidaymakers going to other countries, will lay themselves open to financial disaster this summer.

Around 10,000 people are expected to fly from the UK to watch England’s matches and almost 24 million will take breaks elsewhere. Many will not have insurance to protect them if accident, illness or some other catastrophe strikes.

One in five travellers going abroad do not have cover, often because they believe that having a European Health Insurance Card (EHIC), entitling them to free state medical care in participating countries, makes it unnecessary. By the time they discover their mistake, it can be too late to rectify.

In 2016, reciprocal healthcare agreements between the UK and 13 countries, including Russia, came to an end, meaning uninsured travellers requiring medical treatment have to foot the entire bill themselves.

Georgie Frost, consumer advocate at price comparison website GoCompare, said: “Accidents happen, and football fans are just as susceptible to falling ill abroad as any other holidaymaker, whether they’re in Moscow or Malaga.

“Taking a gamble by not getting insurance could leave you with a huge but unwanted World Cup souvenir.

"Overnight hospital stays equal large bills, and if it’s so serious that you need an air ambulance to fly you back to the UK, you won’t see much change from £20,000.”

Countries not covered by the EHIC include Turkey, Ukraine, Georgia and many other former Russian republics.

It is accepted by all 27 members of the European Union plus Switzerland, Iceland, Norway and Liechtenstein. But state provision varies considerably, and few countries will cover the full cost of care, meaning the holder could still have to pay hundreds if not thousands of pounds.

In the US, which is outside the EHIC area, a broken leg could set you back £45,000 and a heart attack £80,000.

There are also no guarantees that if you are picked up by ambulance abroad you will be taken to a state-run hospital.

In resorts, many smaller hospitals and clinics are private and do not accept the EHIC, so you will be billed for the full cost of treatment. And the EHIC will not help with other common holiday problems, such as cancellation and baggage loss or damage.

This means that anyone going abroad should pack an insurance policy. Look for one with at least £2 million of medical cover, plus cancellation protection for the total cost of the holiday along with any pre-paid activities and excursions, enough baggage cover to replace everything you are taking and a minimum of £250 for theft of cash.

If you are a regular traveller, a 12-month policy may offer better value than a series of single-trip ones, but ensure that baggage is included, as this is often optional with annual cover.

Compensation for scheduled airline and end-supplier failure is worthwhile, as is payment for delays.

Also, to minimise the cost of making a claim, it is worth opting for an excess of £100 or less.

According to GoCompare, a single trip policy for a 39-year-old man spending two weeks in Russia could cost as little as £5.79 from Travelinsurance.co.uk. Its Super Saver policy has a £15m limit for medical expenses but the holder must pay the first £250 of any claim.

Virgin Money’s Essential Plus policy costing £8.54 offers £10m of medical cover but has an excess of only £100.

GoCompare said there are a wide selection of policies available for under £10 offering similar levels of medical expenses cover, between £500 and £2,000 for cancellation, £500 to £1,250 for baggage and other useful protection.

If you have yet to buy a policy, do not go straight to your travel agent or holiday company. Equivalent cover is almost always available more cheaply online via comparison sites.

The EHIC has to be renewed every five years. If you need a new one, do not be fooled by sites that charge to process applications. Cards are available free from www.ehic.org.uk and it is straightforward to apply.

Although football fans heading to Russia can leave their EHIC at home, Ms Frost recommended that they, and anyone else going abroad, pack a credit card with a reasonable limit in case of emergencies.

She said: “A card may come in handy to settle any medical bills before claiming on your travel policy when you get home.

“Just make sure you receive an itemised bill to show your insurers what you’re asking them to pay for along with any other information they require to process a claim.”