Any idea that the exodus from Britain of those settling abroad might be waning appears wildly premature. The latest survey predicts 1.8 million Britons retiring abroad by 2025 and 3.3 million by 2050. The survey, on behalf of NatWest International, provides further evidence that the majority of those making the lifestyle change do not look back.

Nine in 10 expats said they enjoyed better quality of life and six in 10 said they did not intend to return to the UK.

Canada was rated the best country to emigrate to, followed by New Zealand and Portugal.

However, beneath the glitz lurked a less happy picture. Three quarters of those surveyed admitted to feeling homesick some or all the time, missing friends, the British culture and sense of humour.

What the survey might usefully have expanded on are health concerns, especially among older expatriates.

Many of those retiring to the sun are doing so at a time when body and brain begin to disintegrate at increasing speed. Local provision of healthcare may be either inadequate or inaccessible to the expatriate.

The language barrier can loom large. Hospital practices may disturb - the National Health Service in Britain has its critics but patients do not generally rely on relatives bringing in lunch, which is routine in some Mediterranean states.

Most expatriates can benefit from medical insurance. For others it is a must. Unless expats are guaranteed full access to healthcare in their adopted state, and standards there are acceptable, skipping cover is flirting with disaster.

Distress and financial hardship can strike when expats are denied care expected as a right. Since NHS access rules were tightened in 2004, the individual who seeks to return to the UK for "free" treatment may also be in for a disappointment.

Just like its continental neighbours, Britain has clamped down on "health tourists". France, the Netherlands, Spain and several Swiss cantons have taken similar steps.

However, these countries offer generally excellent medical services, with hospital-acquired infections much less common than on NHS wards. The gap is recognised by insurers.

David Pryor, senior executive director at MediCare International points to "consistently better" healthcare across much of Western Europe compared to Britain. He said: "The French are rightly proud of their healthcare system and it is still true that access to specialists is quicker, waiting times for operations are lower and certainly hospitals and clinics are cleaner."

Insurers have responded by offering schemes aimed at people who spend most of their lives in continental Europe but a proportion in their home state - in many cases the UK. Limiting the scope helps limit the premium.

As the name implies, Exeter Friendly Society's Spain Residents Plan is mainly restricted to treatment within the country, but limited benefits apply in UK. A 40-year-old would pay €60.67 a month and a 45-year-old would pay €70.76 a month.

Another plan aimed at Spain's burgeoning expat community is Bupa International's Health Plan Complete. It gives comprehensive acute cover in Spain and another, designated, European country.

Obviously, policyholders tend to select their home country as their designated state. But this is not essential. Unusually, the plan differentiates between genders. A man aged 40-45 would pay €76.90 a month and a woman 40-45 would pay €103.70 a month.

Beyond Europe, in the Middle East and the "White" Commonwealth expatriates are being asked to prove they will not burden overstretched national health services.

People who emigrate to Australasia and North America are unlikely to get a visa if they are seen as likely to take more from the economy than they put into it. Mandatory health cover is one solution. In Australia, medical insurance premiums attract substantial tax breaks.

Most top spots for emigration in the Natwest survey offer quality of care that makes medical repatriation benefit unnecessary. However, once you move beyond the developed world, repatriation and/or air carriage assumes vital importance.

Assistance companies, contracted to insurers, specialise in emergency medicine. Their job is to get the patient to a suitable hospital with minimal delay.

Their responsibilities may go further than the purely medical. For instance, during the recent inter-tribal strife in Kenya, an American policyholder whose wife's ethnicity put her at risk, faced the threat of extreme violence.

The insurer's assistance company organised an armed police team to escort the couple to the local airport and then on to a safe haven in Nairobi.

Full story from www.telegraph.co.uk