Researchers at St George's Hospital, London have discovered an increased risk of autism in children whose parents had migrated to Britain from Africa, the Caribbean and Asia.

The size of the increased risk was five times greater for Caribbean people. The risk was also very significant, but slightly less, for African people and much lower, but still present, for Asian people.

The research covered 428 children diagnosed with autism during a six-year period. They found no increased risk in children whose parents who had migrated to the UK from other European countries.

Autism is a severe lifelong developmental condition which affects people's ability to communicate, form relationships and interact socially.

The lifetime cost to society for someone with autism is estimated to be £4.7m.

The Foundation for People with Learning Disabilities says that Autism costs the UK almost £28bn a year. Adults with autism cost £25bn a year, while for children the figure is £2.7bn.

If immigration can increase the risk of autism in children from the third world then this is yet another good reason, if another should be needed, for stopping all non white immigration into Britain.