INFANT deaths and birth deformities in Britain may have been increased by fallout from the Chernobyl nuclear power plant disaster, according to research in the North-East.

Clouds of radioactive gases were released into the atmosphere following an explosion at the Soviet plant in 1986.

But a researcher based in the North-East believes the true impact has yet to be fully assessed and could cause grave concerns across Britain.

John Urquhart, the statistician who discovered leukaemia outbreaks in pockets around the Sellafield nuclear plant in Cumbria, studied information from 15 health districts in England and Wales.

He discovered significant variations in levels of congenital malformations and baby deaths in 1986.

Prior to the Chernobyl disaster, infant death rates and birth defects were on the decline, but figures showed that trend was reversed in the wake of the nuclear fallout, he said. The North-East experienced a distinct jump in congenital deformity and infant mortality rates after the Chernobyl explosion.

Mr Urquhart, based in Newcastle, said: ''We do not know if there is any long-term damage to the reproductive system of people.

"The one thing we do know is that we have been too complacent about the extent to which Chernobyl affected Western Europe.''

Mr Urquhart wrote a paper on national health studies after Chernobyl and assessed health records from 1983 to 1992.

He calculated that added radiation could have accounted for more than 600 extra cases of Down's Syndrome, spina bifida, cleft palate and other abnormalities across England and Wales during these years.

Mr Urquhart's findings were presented to the Dublin Institute of Technology's conference on low-level radiation and health last weekend.