An eco-project has introduced goats to clear an overgrown park of small trees and bushes choking chalk grassland.

Five goats belonging to the Old Surrey Downs Project have been delivered to Hutchinsons Bank nature reserve in New Addington, in a joint venture with the London Wildlife Trust, which manages the reserve.

The goats are hard at work eating their way through some of the small trees and bushes that are invading the chalk grassland. Their relocation to the site is part of a scheme to have the goats carry out conservation grazing.

New fencing was erected in the spring months, paid for by the Heritage Lottery Fund in preparation for the animals. Public access on to the site has also been increased.

A spokesman for the Old Surrey Downs Project said: "Everything went really well on the day.

"The goats were very keen to get started on their task and raced off to do so when they were finally released.

"They got stuck into munching the scrub and it looks like they are going to work out really well.

"They used to be on Chipstead Downs doing pretty much the same thing.

"It is better for the environment to have goats doing it than people because of the time it would take, as well as the problems with getting rid of the stuff – we would probably have to burn it."

The goats are held in three specially-designed pens paid for by a £40,000 grant from the lottery fund. The goats are not the only animal lawn mowers expected on the site, as sheep are likely to be joining them in the autumn.

Hutchinsons Bank is a local nature reserve that contains a number of rare plants and insects, including the nationally rare butterfly called the Small Blue Butterfly.

• They are currently looking for people in the local area to help carry out some of the daily stock checks. Anyone interested can phone the Old Surrey Downs Project on 01737 733 933.