Orange juice, with its lack of fibre, can send a spike of sugar levels through the body, which may lead to diabetes in some people

Just one glass of orange juice a day could significantly increase the risk of diabetes.

Research shows that fruit juices, regarded by many as a healthy way to start the day, raise the odds of a form of diabetes linked to poor diet and obesity by up to a quarter.

Eating whole pieces of fruit however, cuts the likelihood of developing the disease which affects 2.5million Britons.

It is thought the lack of fibre in juices may cause dangerous spikes in blood sugar levels, according to researchers from the Harvard Medical School in the U.S.

Britons work their way through more than two billion litres of fruit juice each year - the equivalent of 36 litres for every man, woman and child.

Many enjoy a morning glass as part of their recommended five-a- day fruit and vegetable intake.

But nutritionists have warned that moderation is vital. People should aim to eat a variety of fruit and vegetables for overall health.

The link between Type 2 diabetes and fruit juice was made by tracking the health and habits of more than 70,000 female nurses over an 18-year period.

This found three portions of fruit a day reduced the risk of diabetes by 18 per cent but just one serving of fruit juice increased the risk.

Those who drank three glasses of apple juice a month were 15 per cent more likely to have developed diabetes than those who got through less than once glass a month.

One glass of orange juice a day raised the risk by 24 per cent, the journal Diabetes Care reports.

Overall, a glass of fruit juice a day increased the odds of developing type 2 diabetes by 18 per cent.

The researchers said: 'Our findings of a positive association of fruit juice intake with hazard of diabetes suggest that caution should be observed in replacing some beverages with fruit juices in an attempt to provide healthier options.

'Moreover, the same caution applies to the recommendation that 100 per cent fruit juice be considered as a serving of fruit.'

Dr Joanne Lunn of the British Nutrition Foundation said: 'Juices have their place. They provide a good shot of vitamin C but we have to watch them because they can be quite high in sugar.'

Around two million Britons have been diagnosed with Type 2 diabetes and a further 500,000 are thought to have it but do not realise they do.

Diabetics do not produce enough insulin, a hormone vital for converting sugar into energy, or they make insulin that doesn't work properly. Blood sugar levels are initially kept in check through a tightly-controlled diet and exercise regimen.

However, most suffers will need tablets or insulin injections as they get older. Doctors fear an epidemic of Type 2 diabetes in the UK because of unhealthy lifestyles and are already seeing the condition being diagnosed at much younger ages.

Pav Pank of Diabetes UK, said: 'It is very unlikely the consumption of fruit juices alone increases the risk of developing diabetes. There are a number of factors such as being overweight, especially around the waist, an unhealthy diet and a lack of physical activity.'