Plans to control grey squirrel populations by using oral contraceptives have been welcomed by the county's nature charity.

A government-approved mass birth control scheme to cut the number of Britain's invasive grey squirrels is producing hopeful results, researchers have said.

The plan involves enticing grey squirrels into feeding boxes only they can access by using pots containing hazelnut spread, which are spiked with contraceptives.

Grey squirrels cause damage to woodlands by stripping bark from trees aged between 10-50 years, and are also one of the main reasons for local extinctions of red squirrels in large areas of the UK.

Environment minister Lord Benyon described invasive grey squirrels as "pests" who cause "untold damage in the British countryside".

He said that "important research on oral contraception shows promising signs that could help to eradicate the grey squirrel in the UK in a non-lethal way, as well as helping to recover our beloved red squirrel".

Ben McFarland, head of conservation at Suffolk Wildlife Trust, said: "Grey squirrels do damage woodland and we welcome any science that can work humanely and without causing inadvertent effects on the wider environment."

Work, carried out by the UK Squirrel Accord (UKSA) and the Animal and Plant Health Agency (APHA), is making "vital progress" to find ways to isolate the squirrels so they may then be able to take the contraceptive.

APHA says it has a feeder with a weighted door that excludes most other wildlife while allowing more than 70% of local grey squirrel populations to get in and eat from them.

APHA is testing different methods of keeping red squirrels out of the feeders, so contraceptives could be used in areas where there are both types of squirrel.

Body weight could be key to helping to distinguish between greys and reds, according to the research which currently does not use the contraceptive in the natural landscape.

Further testing and landscape-scale field trials are being carried out.

UKSA now has the funds to cover the research of the grey squirrel fertility control project.

Gideon Henderson, the chief scientific adviser at the Department of Environment, Food and Rural Affairs, said: "Fertility control can be an effective method complementing other approaches to wildlife management.

"This UK Squirrel Accord and Defra funded study aims to produce an immuno-contraceptive that can be orally administered to grey squirrels through a species-specific delivery mechanism.

"This innovative research has great potential to provide an effective, easily-applied and non-lethal method for managing grey squirrel populations. It will help red squirrels - native to the UK - expand back into their natural habitats, as well as protecting UK woodland and increasing biodiversity."

Vanessa Fawcett, of the Red Squirrel Survival Trust, said: "Without effective conservation management, red squirrels could face further local extinctions across the UK.

"Research into developing an oral contraceptive for the grey squirrel is at an advanced stage.

"We are deeply grateful to all those who supported us so far on our journey to offer a new solution to effectively manage grey squirrel populations."

Rebecca Isted, of the Forestry Commission, said she was "optimistic these trials could eventually lead to a significant change of approach in the management of these animals".

She added that the Forestry Commission is updating the government's grey squirrel action plan, and will later set out its aims to better understand and manage the negative impacts of grey squirrels.