Tourists need to be wary of "one-size fits all" travel insurance policies, according to the Association of British Insurers (ABI).
The travel insurance market is extremely competitive, with plenty of options for consumers who require specialist cover, or who require cheap travel insurance.
However, a spokesperson for ABI has warned that many high-street policies do not provide cover for pre-existing medical conditions, "so it excludes them from medical cover".
She said: "The travel insurance market is a highly competitive market and it offers many people a competitive product that suits their needs.
"Be it a pre-existing medical condition such as cancer, or for instance, you are going on a winter sports holiday then you need to look at a different policy."
This announcement follows research by the Post Office that revealed 70 per cent of Britons have missed out on an estimated £13.5 billion in travel insurance claims.
