Overweight people looking to take out life, critical insurance or income protection insurance could find themselves paying up to six times the amount of someone of average weight without any health problems, independent financial advisors warn.

More insurance companies are now charging higher premiums for those with a Body Mass Index (BMI) of 28-29. This is calculated by dividing a person's weight in kilograms by the square of their height in metres.

People with a BMI of more than 25 are considered overweight whilst those with a BMI of more than 30 are obese.

Previously, insurance only became more expensive for those in the obese category with a BMI of around 33.

More than half of all women and 60 per cent of men are now overweight and even if they have no health problems, they could still find themselves paying twice as much for their cover.

Kevin Carr of LifeSearch said: "Height and weight is one of the questions you are asked about when you fill in a form for a life or health insurance quote. If you are considered by the insurer to be overweight they will often ask for a report from your GP and sometimes a medical examination.

"While the insurer covers the cost of these, the likely expectation is an increase in the premium quoted. Typically, we would expect a loading to start at 50 per cent of the standard premium."

And the premiums could be higher for younger people, not to mention those suffering from weight-related illnesses including high blood pressure or diabetes.

Mike Owen, managing director at specialist insurance brokers Special Risks Bureau, told the Observer: "Insurers accept that people over 55 may well put on some weight as they age, however if you're under 55 and severely overweight you can be asked to pay 300 per cent more than the standard premium in some cases."

He added that many people can struggle to get cover at all as the industry courts those under 40 and in good health whilst penalising others.