Holiday makers should make sure they hold a new European health insurance card when they travel as the old E111 form will not cover them anymore, advises a price comparison website.

The new card is free to all UK travellers and entitles the holder to free or reduced-cost essential medical treatment in all EU countries as well as Switzerland, Iceland, Norway and Lichtenstein.

Without the card holidaymakers' travel cover could be void and having one could save them up to £150 on top of treatment costs, claims moneysupermarket.com.

Nearly two-thirds of British adults are unaware of the new health card which replaced the long-standing E111 form at the start of this year and 58 per cent believe the old form will still cover them for free or reduced cost medical treatment abroad.

"Awareness of the replacement card is alarmingly low, despite the fact that it's been around for nearly a year now," said Richard Mason from moneysupermarket.com.

"Even basic medical treatment in mainland Europe doesn't come cheap, so this card could save you a lot of unexpected financial pain. Worse still, some insurers may not pay out if the claimant hasn't got one."