A link between type 2 diabetes and obesity has been discovered.

A study by King's College London found a mechanism in the immune system that causes the relationship.

It has been identified as a protein called T-bet.

The research, which made use of mice, was completed by Dr Jane Howard and Professor Graham Lord.

When the protein was removed from the rodents, the link between obesity and the diabetes reduced significantly.

"When T-bet was absent, this altered the relationship between fat and insulin resistance; the mice had more intra-abdominal fat but were actually more sensitive to the glucose-lowering effects of insulin," said Dr Howard.

The numbers of those with type 2 diabetes have doubled since 1980, with 370 million suffering from the condition worldwide.

The results raise hopes of providing new treatments for the condition, and eradicating the link between obesity and diabetes.

Dr Howard said: "This is just the start. The idea that the immune system can impact on metabolism is very exciting."