Torrential downpours which hit last week and left swathes of England and Wales under water were officially the worst in more than 200 years of record keeping, according to figures released by the Met Office Thursday.

Rainfall was more than double the seasonal average, with the early summer months of May to July witnessing 382.4 millimeters (15.06 inches) of rainwater, topping the previous record of 349.1 millimeters in 1789, said officials.

Deluges in 32 counties, covering the thousands of square miles stretching from Devon to Yorkshire, broke records dating back to 1914 by more than 25 millimeters, the meteorologists added.

Forecasters predict the weather to remain unsettled until early August, with satellite images for the weekend suggesting a further 20 millimeters of rain are possible across parts of the southwest.

Further analysis of recent data by Met Office scientists showed that in the past three months, Gloucestershire and neighboring areas experienced more than 320% more rainfall than the average for the previous three decades.

Met Office officials gave government and emergency services two days warning that intense rainfall was likely. During the worst rains, daytime darkness saw demand on the National Grid rise 3% as offices switched on more lighting.

Dr. Peter Stott, a senior climate scientist at the Met Office said downpours of such magnitude are set to become more frequent, as climate change drives up the temperature of the atmosphere.

"These one in 200 year events are very likely to become more common. When it rains, it can rain much harder, because the atmosphere can hold more water in a warmer world," he said.

If greenhouse gas emissions continue rising, Dr. Stott said Britain could eventually experience temperatures similar to those in Japan. Intense rains may release more than double the five inches of water that fell in just 24 hours on parts of Worcestershire and Oxfordshire last week, he added.

Dr. Stott is the co-author of a paper published Friday in the journal Nature which shows for the first time that climate change driven by human activity is altering rainfall patterns around the world.

The heavy rains were triggered by a rare abnormality in large-scale air currents that saw the high-altitude westerly jet stream linger south of Britain instead of making its seasonal shift northwards. The high speed current brought a series of low pressure weather systems on to the British mainland, which merged with warm air from the continent, making it rise and release its moisture as rain over central and southern Britain.

The intense rains in the south have been countered by substantially lower than average rainfall in Scotland. From May to July, most of the region has received 50mm less rain than the average calculated since 1914.

Climate change models predict that Britain will experience longer, drier summers and wetter, warmer winters, making the summertime rains more of an aberration of the weather than a direct result of climate change.

By the end of the century, scientists predict Britain will become warmer by between 2 degrees Celsius and 6 degrees Celsius, with the climate in the south of the country becoming more like continental Europe.

The increased risk of flooding as climate change takes hold will demand huge investment in new flood defences, Dr. Stott said. Plans to bolster the Thames barrier, which guards London and property along the estuary against storm surges, may reach £25 billion ($50 billion) if the Environment Agency decides it needs to build a second barrier. Less costly options are also under consideration, including an upgrade of the existing barrier.

Explainer: Future of Forecasting

Short-range weather forecasts for individual towns and villages could be in use by 2011. A £120 million ($240 million) upgrade of Met Office computers will give forecasters the power to warn places at risk of severe weather up to 12 hours in advance.

Current forecasts can predict the weather only within a zone 60 kilometers across, but with more powerful computers, researchers at the Met Office's headquarters in Exeter hope to narrow the focus to an area just 5 kilometers wide.

"It means people living in an individual town can be told when something nasty is on its way," said Brian Golding, the Met Office's head of forecasting research.

Further research is aimed at making forecasts more accurate by using computers to crunch through and combine predictions from multiple weather scenarios.

Since the 1987 hurricane that was dismissed by former weatherman Michael Fish, the Met Office's computers have improved in resolution by a factor of 35, said Dr. Golding.