West Somerset MP Ian Liddell-Grainger has welcomed “drastic” 1,000-fold increases in maximum fines for polluting water companies.

But, he warns, the tough penalties will only succeed if they are firmly applied by the courts.

And meanwhile, he says, it is likely to take years to purge the effects of damaging nitrate pollution from many important wildlife habitats.

New Defra Secretary Ranil Jayawardena has announced that the maximum penalty for water companies which pollute rivers, shorelines or the sea will rise from £250,000 to £250 million.

The move is designed to appease mounting public anger that the water industry has been presiding over hundreds of illegal discharges from overloaded sewerage systems.

Complaints have come from as far as the northern French coast where trawler owners have complained water quality in their traditional fishing grounds is now being compromised.

Mr Liddell-Grainger, MP for Bridgwater and West Somerset, said the elevated penalties were a clear sign that the Government was determined to enforce a clean-up of coastal and inland waters.

“Any set of measures such as these, which are firing a very loud shot across the industry’s bows, are to be welcomed,” he said.

“However it is a matter of great regret to me that it has taken a slew of highly-damaging and well-documented illegal sewage discharges in recent months to achieve this response when better monitoring and more open reporting could have led to earlier intervention.

“It is now up to the courts to apply these sanctions forcefully in order to send a very clear message to the water companies that the country will not tolerate their irresponsible polluting activities any longer.”

Mr Liddell-Grainger’s constituency includes part of the Somerset Levels where the status of some internationally-protected wildlife sites is now under threat thanks to excessive concentrations of nitrates which are destroying rare plant and animal life.

The problem has been linked to water companies’ failure to upgrade treatment to cope with an increased sewage load from the thousands of new homes that have been built around Taunton and Bridgwater, leading to elevated nitrate loads in local rivers.

The situation is so serious that local authorities imposed an embargo on new house-building until mitigation measures could be agreed.

Mr Liddell-Grainger added: “I am relieved that improvements are now underway but they are going to take some years to be put in place and in the meantime water quality across the Levels will continue to be adversely affected.

“But even when the improvements arrive it is going to take many long months and years to flush out the system and return it to good quality. My only hope is that we do not, in the meantime, reach a point of no return and see the area stripped of its prestigious international status.”