Protesters fighting plans for wind turbines on moorland in Bronte country have had four campaign banners slashed and defaced by vandals.

Anthea Orchard, chairman of Thornton Moor Wind Farm Action Group, which is challenging plans by Banks Renewables to build up to four turbines on moorland south of Denholme , said signs valued at hundreds of pounds have been destroyed in a spate of attacks over the past five days.

Members of the group have reported the damage to West Yorkshire Police, but vowed to replace the banners and continue their fight against the proposals.

Mrs Orchard, of Denholme Gate, said: “We’re clearly upsetting someone, but to resort to vandalism is cowardly.

“We set up a forum on our website for people to give us their views, so long as they’re not abusive or obscene. If someone has something to say, we’ve given them a channel to do it.

“To commit criminal damage just shows they are cowards.”

The group has had backing from The Bronte Society, which claims turbines may spoil the “unique countryside” believed to have inspired the Bronte sisters’ world-famous novels, and has now also won support from Bradford and District’s UKIP branch.

Its members will join forces with the political party – which it claims is the only one to speak out against wind power – to mount a campaign against the “destruction” of the green belt.

Jason Smith, UKIP Bradford chairman, said: “Local people have had a gut full of wind turbines being built in their backyards with no process to oppose them – they’ve had enough of local councillors standing idly by and ignoring their pleas for help.

“Together with hundreds of local people we intend to fight wind turbine applications that do not have support of local people.

“Currently we are disputing an application on Thornton Moor which we expect to be overturned. We’ll either bring down wind turbines or we’ll bring down the local councillors who support them.”

For more information about Thornton Moor Wind Farm Action Group, visit sayno2windfarm.org.uk.