The consumer champion carried out an investigation into common barriers to finding affordable cover, gathering the experiences of 63 of its members who had experienced problems buying travel insurance in the past two years.

Among these members, medical conditions (22 out of 63) and age (21) were most commonly identified as being the source of their problems, and travel insurance was where they most often reported hitting barriers (26).

Price was most commonly reported as the main issue when accessing cover (31 out of 63), though about a fifth (13) said their main barrier was that few or no insurers offered any cover at all. Meanwhile, around a sixth (10) said few or no insurers offered the cover they wanted.

After medical conditions, the second most commonly flagged cause of difficulty among those surveyed was their age (21 out of 63). While travel insurance is not the only type of policy where getting older can work against you, it gets markedly more expensive and harder to find once customers pass 65 – even if they are in good health.

In separate mystery shopping research on a major comparison website, Which? found that once a travel insurance customer reached 70, not only did they have fewer quotes to choose from, but the average of their cheapest five quotes nearly doubled, compared with what they were offered at the age of 65.

Posing as a 55-year-old travel insurance customer, Which? had 76 quotes to choose from, but this tanked to just seven quotes for an 80-year-old.

The vast majority of travel insurance providers can cover medical conditions and often for a reasonable price. However, severe or unpredictable conditions, such as heart disease or bipolar disorder, or an illness still in the process of being diagnosed, can send insurers running for the hills.

One Which? member said that declaring his wife’s irregular heartbeat results in ‘either a refusal to insure or astronomical premiums’ for the couple’s annual worldwide cover – with one insurer quoting as much as £3,200.

Jenny Ross, Which? Money editor, said: “For many insurance customers getting insurance is straightforward – but for a small fraction, finding cover can routinely be a nightmare. However, not all hope is lost.

“If you struggle to get insurance because of medical conditions or your age, there are some resources that can help you locate specialist insurers that lie off the beaten track of comparison websites.

“If there’s relevant context to your history or circumstances that you can’t communicate on an online form – or you’re unsure how to accurately fill one out – contact the insurer directly by phone or email to speak with a human being.”