Weather experts have warned many seaside towns could disappear beneath the waves in the next 200 years because of global warming.

Brighton and Hove could be lost to the English Channel by the year 2200 according to a report published yesterday by University College London's Benfield Hazard Research Centre.

The study took two months to complete and looked at the effect rising sea levels could have on the landscape of Britain, based on satellite images.

In the worst case scenario, Brighton and Hove would be submerged along with Worthing, Bognor and Eastbourne. Only the Sussex Downs would survive.

Britain would become a series of islands made up of hills and valleys and most of London would be lost.

This would only happen if the ice sheets in both the east and west Antarctic melted, causing sea levels to rise 84m.

The report said this was unlikely as global warming was being taken more seriously by world leaders, who are working to reduce carbon emissions.

However, there was still a one in 20 chance the west Antarctic ice sheet could melt, causing a rise of 7m.

Professor Bill McGuire, who led the research team, said: "It is clearly the west Antarctic ice sheet which is most worrying. If this melts, along with the continued thermal expansion of sea water, we could see many coastal cities disappearing beneath the waves in the next 200 years."

Chris Todd, of Brighton and Hove Friends of the Earth, said rising sea levels would be a disaster for Sussex.

He said: "Undoubtedly climate change is going to hit us hard and cost us economically as well as environmentally.

"For every metre sea levels rise, we are going to have to spend vast sums of money shoring up defences.

"We will see more than just a rise in temperatures, there will be much more erratic weather as we have seen recently with flooding in Lewes and Uckfield, flash floods in Glastonbury and Yorkshire and last week's heatwave.

"Erosion of the Seven Sisters will be much faster than it might have been and the impact would be disastrous for Brighton and Hove.

"It doesn't take much imagination to realise that if sea levels rise the seafront would go, which would devastate the economy."

However, he was cautious about the report's findings.

He said: "We have seen large-scale predictions previously. The problem is the huge uncertainty surrounding what will happen."

Rising sea levels are already threatening to submerge the road between Selsey Island, near Chichester, and the shore.

Houses in Fairlight, near Hastings, are under threat because the cliffs they are built on are collapsing.

The study was commissioned by digital television channel UKTV History to promote its new series The British Isles: A Natural History, being screened every evening this week at 9pm.