A rare species of butterfly is on the increase in Sussex thanks to work by volunteers.

The silver-spotted skipper was in danger of leaving land near Alfriston owned by South East Water because scrub was taking over the chalk grassland it prefers.

South East Water was given a Government grant to manage the land by getting rid of the scrub.

It was hoped this would encourage other species including the grayling and chalkhill blue to stay.

The company has been working with Sussex Butterfly Conservation and English Heritage.

Seven years on, research by Sussex Butterfly Conservation has revealed numbers are increasing across the site.

In one day, 23 different species of butterflies were spotted by Roy Neeve, of Sussex Butterfly Conservation, who is leading a team of volunteers studying and counting the butterflies.

To keep the scrub away, the land is used for grazing, while in the winter months volunteers clear the scrub, which includes hawthorn.

Emma Goddard, environmental co-ordinator for South East Water, said: "The work is incredibly important. The species we are talking about are very rare.

"It is one of the key areas in the country where the silver-spotted skipper breeds."