Martin Lewis has issued an urgent message to Britons travelling to Spain and France this summer as a change in regulations could leave people without help and protection.
The financial expert advised holidaymakers to check two vital documents before jetting off to their holiday destination.
He warned viewers about expiring health insurance cards, including the transition from the European Health Insurance Card (EHIC) to the Global Health Insurance Card (GHIC).
The cards guarantee British tourists access to state-run hospitals and GPs in all the covered countries at the same price as locals.
Countries which are protected by the card includes all EU countries, as well as Norway, Iceland, Lichtenstein and Switzerland.
But, Lewis warned that 5.4 million of the old EHICs are set to expire this year.
The card can be renewed for free at nhs.uk.
"To renew it, it is always free. If anybody is charging you, they are a shyster trying to steal your money," the money saving expert said.
"There is no such thing as a fast track."
He added that the cards are only advisable but they could prevent Britons from needing to pay the excess on travel insurance.
Those without a card and require assistance on holiday can contact the NHS and ask for a provisional replacement certificate.
In addition Lewis discussed the requirements for passports to remain valid.
Passports must be under ten years old on the day a person enters a country and it must have at least six months left on the document from the same day.
He added that the Passport Office currently advises people to allow "up to 10 weeks" for a renewal, though he had heard of longer delays.
He said: "Let me be plain...the travel insurance company will not allow you to claim if [an invalid passport] is the reason you can't go on holiday.
Since the UK left the EU, Britons now need to have at least three months left on their passport to be able to travel to Europe.
Travellers could could be turned away if their passport is in too bad of a condition.
The Government website warns: "You must replace your passport if it has more than reasonable wear and tear because you may not be allowed to travel with it."