Aviva has updated 250 of its occupational classes in order to offer income protection to people in a wider range of occupations.
The insurer said the review of its occupational classes will mean lower premiums, an increase to the breadth of cover and a less strict definition of incapacity than offered now.
Aviva said around 95% of occupations will now be underwritten on an own occupation basis, rather than a suited occupation basis.
It has also reduced the risk it previously attached to some occupations, such as journalists, chartered surveyors, vets and scientific professionals.
Aviva will also now offer cover to 21 occupational classes which it previously declined, such as roofers, tillers and scaffolders.
The non-medical limits on Aviva's income protection have been raised in many cases, so that applicants of all ages will get a higher level of automatic cover without medical examinations, regardless of disclosure.
Jon Parker, chief medical underwriter, Aviva, UK Health, said: "With the proposed reform of the welfare state it is now more important than ever for people to adequately protect themselves against the loss of an income through illness or injury.
"We have rigorously challenged the market's classification of occupations and industries at certain prices and the particular definitions of incapacity, as the risks once associated with many occupations are no longer as high thanks to advances in technology and better workplace health and safety.
"As a result, we have significantly improved our terms and premiums for customers in line with the risk their occupations bring today, not 20 or 30 years ago."
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