The study, led by Dr Paul Bennett at the University of Edinburgh and Professor Susan J. Smith at the University of Durham, says that the proportion of applicants refused cover outright is also more than generally believed, at 1.5 rather than one per cent. Researchers found enormous variability between companies when it comes to how many policies are 'rated' for heavier charges.
Between none and 18 per cent of policies had higher premiums for people experiencing or at risk of developing a variety of health conditions. There were similar differences in how many applications were declined - between 0.25 and six per cent.
Dr Bennett said: "Our project arises from growing concern about uneven access to financial services, especially those offering protection to individuals and families at a time when state safety nets are thinning out.
"There are also worries that new developments in bioinformation, especially around human genetics, could increase this social and financial divide."
The researchers acknowledge that selling life insurance does depend on health discrimination. But Professor Smith said: "Although UK insurance underwriting is generally rigorous, the question is where as well as how and why to draw the line."
The study found that 78 per cent of insurers now routinely package life and critical illness cover, and more than 53 per cent roll life insurance into a wider mortgage protection service.
Professor Smith said: "It is these insurers who draw the line most tightly, perhaps reflecting the fact that more health information is gathered to underwrite packages than for life insurance alone.
"Nine in 10 insurers say they routinely refer to this extra health information when assessing the life insurance com
Contact: Alexandra Saxon
Economic & Social Research Council