Mr Meacher made the announcement at a conference which heard that important wildlife sites are threatened by over-abstraction and pollution. BBC News 24 environment correspondent Tim Hirsch was at the meeting.

The government's water watchdog Ofwat is currently preparing its review of water prices which will determine how much the privatised companies can charge customers from 2000 to 2005.

Environmentalists are concerned that pressure to keep prices down could mean that Britain's wildlife will end up the loser - that was the starting-point for a conference in London organised by the Royal Society for the Protection of Birds and English Nature, entitled What Cost Water?

Wildlife in danger

Only 12 pairs of bitterns remain in the wild

The RSPB says that 80 important wetland areas of Britain, all sites of special scientific interest, are threatened by sewage pollution or over-abstraction of water from rivers and underground bore-holes.

One example is Strumpshaw Fen near Norwich, which provides an increasingly rare reedbed habitat for one of Britain's most endangered birds, the bittern - just 12 pairs remain.

There are no fewer than 23 boreholes within a 3km area taking water from underneath the fen, lowering the water table and threatening the bittern's habitat.

Minister to make changes

The Environment Minister, Michael Meacher, was expected to use the conference to announce the outcome of a government review into the system of "abstraction licences" given to water companies.

But, because of some last-minute quibbles from Treasury, the announcement has been delayed until next month.

However, Mr Meacher made it clear that he will change the current system which allows companies to take water from rivers at almost no cost, under indefinite licences issued after World War II when water was plentiful.

He is likely to put a time limit on new licences, and to use financial incentives to persuade companies to take less water from natural sources.

Ofwat backs price cuts

English Nature says �220m is needed to protect 80 endangered wildlife sites

Also at the conference was the Director-General of Water Services, Ian Byatt, who told the audience of representatives from the industry and environmental pressure groups: "Reasonable prices for customers and improvement to the environment are not mutually exclusive. We can have both."

But some green groups doubt that concerns about wildlife will feature strongly in the current price review. They point to a survey carried out by the Environment Agency suggesting that 95% of consumers would prefer an improved environment to reduced water charges.

According to English Nature, meeting that public demand will not break the bank: it estimates that �220m is needed to protect those 80 endangered wildlife sites.

It sounds a lot, but put against the likely water investment programme of �24bn for 2000-2005, the organisers of the conference say it is a small price to pay to preserve the rich wildlife of our wetlands.