Potteric Carr, on the outskirts of Doncaster, is a nature reserve of meadows and lagoons designed to attract disappearing species such as the bittern, lapwing and water vole. For the past two years WWF and its partners, including HSBC and Yorkshire Wildlife Trust, have been developing an important extension to the reserve, which now covers some 200 hectares (around 500 acres).

"The project recreates part of the old wetland landscape that existed on the edge of Doncaster 200 years ago," explained Rob Oates, manager of WWF's Natural Rivers programme. "It was drained way back in the 18th century for agricultural use, and again in the 19th century when the railways arrived."

Now, the area has been restored to its natural tranquillity and beauty – and offers visitors a network of paths, viewing hides and rest areas far removed from the bustle of the nearby town centre.

The extension was formally opened by Terry Waite, a WWF ambassador and former special envoy of the Archbishop of Canterbury. In a brief speech, he spoke of his five years of captivity as a Beirut hostage, and recalled the time when, after years of incarceration, he saw the sky again for the first time.

"All of us take that kind of thing for granted," he declared. "But for me, seeing the sky and feeling the wind on my face was a simple experience, and one I'll never forget. It inspired me to do as much as I possibly can for the environment."

But, he added, he was appalled by the fact it was taking people so long to wake up to today's huge environmental problems. "We can't continue ruthlessly raping the planet and treating the environment in a casual, offhand way. Instead, we must engage with it."

Clean water, he declared, was crucial to mankind and the planet. That was why he was visiting the Potteric Carr wetland, which will help naturally to purify waste water from 10,000 homes and industrial premises in the area.

Robert Napier, chief executive of WWF, described Potteric Carr as an exciting project that would bring great benefit to the local community. And Dyfrig John, chief executive of HSBC, spoke of the £1.5 million project as a national example of how wetlands can mitigate the ravages of climate change.

Not only will Potteric Carr attract more rare wildlife, but it will also be used to demonstrate how a nature reserve, flood defence system, water treatment works, recreation area, education centre and tourist attraction can be created cost effectively and on one site.

"WWF will use Potteric Carr to persuade decision-makers in government and industry to provide more cities with similar wetland sites," Robert Napier added.