Would be travellers have been warned that if they plan to fly without informing their travel insurer of any pre existing medical conditions, you may not be covered for every eventuality.

The warning comes from Sainsburys Travel Insurance which shows that around 1.3 billion people travelled abroad but refused to tell their insurers of their prior relevant medical history.

Sam Marrs of Sainsbury's says: "The purpose of travel insurance is to ensure that if a disaster does strike, you will get the necessary care and support. Withholding key information such as any medical conditions could mean your cover may be invalidated and in the worst of cases, this could mean facing large hospital bills or arranging your own repatriation."

They added, "It is important to be honest with your insurer and provide all the information they ask for. It is a fiercely competitive market so if you have a common medical condition there is a good chance you will find an insurer to cover you for a fair and competitive premium."