The Department of Health has warned Britons that their holidays could be invalidated because millions of European Health Insurance Cards (EHIC) are set to expire soon.

According to the Department of Health, 1.5 million EHIC cards will expire by the end of this month and a further 1.5 million will not be valid after March 2009.

The EHIC cards were introduced three years ago as a replacement for E111 and holders benefit from medical treatment within European Economic Area (EEA) although reports suggest that some travel insurance policies are invalid without an EHIC.

Paul Siddell, overseas healthcare programme manager at the Department of Health said: "Many Britons are putting themselves at unnecessary risk by not checking their EHIC expiry date."

He further added: "If you're travelling in Europe it's vital that you carry an EHIC, as well as comprehensive travel insurance."

Statistics show that an estimated 28 million Britons currently hold an EHIC card. At the same time, a recent study shows that more than 50 per cent are unaware that the card has an expiry date.

According to the Department of Health, British holidaymakers should ensure that they check the validity of their European Health Insurance Cards or risk having invalidated travel insurance.