The Social Issues Research Council (SIRC) has said the scale of childhood obesity in the UK has been grossly exaggerated.

The think tank suggested that Britain’s childhood obesity epidemic is based on little more than "unsupported speculation".

But it’s findings have been tempered in the national press by the finding that the SIRC receives part of its funding from leading food companies, such as Cadbury Schweppes, Mars and Kellogg’s,

The SIRC said average child weights have increased only slightly in recent years.

The SIRC team, used the 2003 Health Survey for England to assess the average weights of the UK’s children. It found Body Mass Index (BMI) trends have been broadly static for girls and boys aged under 16 from 1995 to 2003.

An average 15-year-old boy weighed 9st 5lbs in 2003, compared with 9st 2lbs nine years earlier. The average weight for a 15-year-old girl was just under 9st 3lbs, nearly a pound higher than in 1995.

The SIRC concluded there has been no "epidemic weight gain in children" in the UK, despite reports childhood obesity has tripled in the last 20 years.

Dr Peter Marsh, the co-director of SIRC, said the data brought into perspective "lurid warnings" that the current generation would die before their parents due to an excess of fast food and lack of exercise.

He added: "There are some overweight and obese kids and yes that is an issue we need to tackle. But it is a slight increase, not the alarming rate people are trying to convince us of."

Marsh said middle-aged people - the most "at risk" age group for obesity according to the report - should worry about their weight, and advocated a "natural attitude" to food for children. "You are never going to persuade kids not to eat Mars bars or drink Coke because that will not work," he said.

"Yes, we should be concerned, but maybe we should be going about this in a different way. Rather than playing nanny nutritionists, we should be more sensible."

Dr Colin Waine, an executive director at the National Obesity Forum, said the report was an attempt to "obfuscate" the real problem - the quadrupling of obesity in Britain in the last 25 years to 22 per cent.

"I just think it is playing down a problem in a very unhelpful way, when people are just beginning to sit up and take notice," he said.

But medical experts have reacted furiously. Rhona Brankin, Scotland’s deputy health minister, insisted the scale of childhood obesity in Scotland is "truly frightening".

Brankin said: "Childhood obesity has been on the increase in virtually all developed countries over the last two decades.

"The statistics are truly frightening. In Scotland, some 20 per cent of 12-year-olds are classified as obese and 33 per cent are overweight. This carries huge health implications for them in later life."