Britain's position as a world leader in stem cell research will come under new pressure from California, where voters have overwhelmingly approved a state initiative to spend $3bn (£1.7bn) on this field of biomedical science over the next 10 years.

Researchers yesterday welcomed the passage of California's Proposition 71, because it would accelerate the development of treatments for degenerative diseases from Parkinson's to diabetes. But they said the government, other funding agencies and the biotech industry needed to agree a long-term plan to support stem cell development in Britain, if the huge Californian fund were not to suck the brightest young scientists over to the US.