BEAVERS may be released into the wild by South West Water in a trial to improve water quality around Roadford Reservoir.

The water company is considering a trial because beavers build dams which trap silt and act as a natural filter.

South West Water said it would cut down on treatment costs and in the long term reduce costs to the customer.

The news follows the escape of a beaver from Lifton over the Christmas period, which is believed to have taken up residence on the banks of the River Tamar at Gunnislake, 20 miles away.

Owner of the beaver Derek Gow is in the process of getting traps made to catch the animal but he told the Times this week that he was waiting for the huge interest, as a result of media coverage, to die down before the traps were laid as the beaver was doing 'no harm'.

The reintroduction of beavers, which is happening in Scotland in a trial in May, has concerned some people due to the damage the animals can cause to trees. Fallen trees at Gunnislake first alerted experts to the signs that a beaver was on the loose.

South West Water's environmental officer Martin Ross said: 'Beavers have the potential to clean and improve the water course and help biodiversity and this is possibly a way we could protect Roadford Reservoir.'

He said surveys were being carried out and consultation with landowners and the local community to find out if there would be support for the plan. If there was, a proposal would be put to Government agency Natural England.

'Beavers build small dams in feeder streams which act as a filter and hold back the top soil which in turn holds back phosphates. The result is nice clean water in the rivers and reservoir and in the longer term lower costs for our customers in terms of water treatment and supply,' added Mr Ross.

Derek Gow, who runs Upcott Grange Farm at Lifton where he keeps 24 beavers under licence from Natural England, said introducing beavers would be a great thing: 'It is long overdue and from an ecological point of view it really makes sense. It makes the process of cleaning water more sustainable.

Beavers have not been seen in the wild for 250 years after they were hunted to extinction for their fur and meat. Mr Gow said such was the interest from people trying to find the animal at Gunnislake that he planned to leave it a few weeks before setting the traps.

'There are so many people wandering up and down to find where it is and my fear is that if we trap the animal someone might let it out and then it will become more difficult to catch it again because beavers are not stupid.'

The beaver expert said the 40kg specimen , which hails from Germany, was preparing for winter and creating a food pile in the river: 'I was down there at the weekend and I know where it is. It has taken small scrub and willow. It will be fine there because it is a wonderful beaver habitat anyway.'

The land is privately owned and none of the trees are for commercial use. Beavers are vegetarian and live on a diet of reeds, bark and leaves. They seldom stray more than 50 metres from water and although they can fell trees they are described as docile.

Mr Gow added: 'In the Middle Ages it was an incredibly valuable animal to kill. If you could kill a beaver that would be three years' wages. That's why there are no beavers any more. It is a native animal and it should be here.'