A fragment of a huge Saxon forest that once covered much of the West in the 9th century is being fought for by locals using 21st-century techniques.

For the campaign to save Birds Marsh Wood on the edge of Chippenham in Wiltshire is being conducted online using the social networking site Facebook.

King Alfred had a hunting lodge nearby to ride out in the ancient Selwood Forest, but what he would have made of the Facebook group no one knows. However, locals reckon he would have certainly approved of the attempts to save what is one of the few remnants of his hunting ground.

Selwood Forest used to stretch from deepest Somerset all the way up to north Wiltshire to join the equally old Bradon Forest. Large swathes still remain around Longleat and the Wiltshire-Somerset border, but little remains near Chippenham, where Alfred the Great had his royal playground.

Best way to get the word out

Now developers have started the ball rolling to build 46 new homes on land around one remining patch, Birds Marsh Wood, that locals say would ruin the popular woodland haven.

The developers have submitted an initial request to district planners, with a formal planning application expected early this year.

One resident, Simon Main, turned to Facebook to spread word of the threat. In just 10 days, more than 700 people have signed up to his Facebook group, with another 900 friends asked to join.

"About 15 years ago, there were similar plans to build there and the residents at the time fought it using traditional means, such as organising a group and writing letters," he explained.

"We will be doing all that, but first I started the group on Facebook because I thought, in 2009, it was the best way of quickly getting the word out there. It's a great way of alerting people to the threat because often these things happen and people who would normally object don't hear about it until it's too late.

He added: "This Facebook group is great because it expands so rapidly. Within two days there were 400 people signed on and there is almost a thousand people waiting, who are people who have forwarded it on to their friends. We have people from all over the world who know Birds Marsh."

Local town councillor Paul Darby is working with Mr Main and other residents, and a more conventional, face-to-face meeting is planned for next Sunday, January 11. The venue – appropriately – is the King Alfred pub close to the wood.

"Last time this wood was threatened, there were lots of people doing different things but this time we want to bring everyone together – the people on Facebook and maybe the pensioners who fought last time," explained Mr Main.

Sheila Davis, 77, believes the wood is a "jewel in the crown" for Chippenham.

She said: "This development would be an abomination. It would be a crying shame if the wood was torn down for yet more housing."

And the Facebook group is also providing additional resources for the campaign.

Mr Main said: "I've noticed people have started taking cameras out to the woods when they go, taking beautiful pictures of the scenery and then posting them on the Facebook website. It has raised the awareness of the wood itself."