Britain was warned Monday that it may have to choose between whether to protect its towns or its countryside from flooding in the future.

While parts of rural Somerset in southwest England have been underwater for almost a month, Lord Chris Smith, chairman of the Environment Agency, said the public body had to make "sensible choices".

Some villages have been marooned on the Somerset Levels, an area of drained marshes partly below sea level. About 65 square kilometres (25 square miles) have been flooded.

The Environment Agency has come under fire for its handling of the floods.

But Smith warned there were "no quick fixes in the face of this kind of extreme rainfall".

"Yes, agricultural land matters and we do whatever we can with what we have to make sure it is protected," he wrote in the Daily Telegraph.

"Rules from successive governments give the highest priority to lives and homes; and I think most people would agree that this is the right approach.

"But this involves tricky issues of policy and priority: town or country, front rooms or farmland?

"Flood defences cost money," he said, asking how much taxpayers should spend on protecting various places, communities and livelihoods.

"There's no bottomless purse, and we need to make difficult but sensible choices about where and what we try to protect."

Parts of southern England have seen the wettest January since records began in 1910, figures showed on Thursday.

Southeast and central southern England had more than twice the average rainfall, with a record 175.2 millimetres (6.9 inches) falling between January 1 and January 28, beating the previous monthly record of 158.2 millimetres set in 1988.

Smith said the tidal surge in December was the highest since that in 1953, when more than 300 people were killed.

Prince Charles, the heir to the throne, is due to visit the Somerset Levels on Tuesday.