Banners opposing proposed new Gatwick Airport flight paths have been slashed to pieces.
Campaigners believe the six-foot-wide banners posted outside homes alongside the A24 were vandalised by opponents.
Communities Against Gatwick Noise Emission (CAGNE) says six of its banners were damaged on Sunday - and another again on Wednesday.
CAGNE chair Sally Pavey said: “Someone has attacked them all with a knife.
“Banners outside six homes were attacked on Sunday. One of the residents came home at six o’clock and found it.
“We had a report of one of the banners we had repaired being slashed.
“The lady did a school run and it was fine when she left and when she came back it was slashed. So we presume it is a local person.”
The later home was near Kingsfold and the others were all about three miles around Horsham, including one at Lower Chickens Farm. The vandalism was reported to police and campaigners hope a witness might come forward.
Ms Pavey said: “Police are sympathetic but unless someone saw what happened and comes forward, there is little they can do.
“But somebody must have seen someone doing it because it is such a busy road.”
She added: “It is really a shock. There are a lot of people saying they can slash our banners but they cannot stop our desire to prevent our communities being destroyed by Gatwick.
“We are just families, mums and dads, who have had our quality of life destroyed.”
CAGNE wants people to take part in a consultation opened by Gatwick, closing today (August 14), on new noise preference routes.
Ms Pavey said: “I really hope people will participate. It is a very important consultation, but it is absolutely full of jargon and very confusing.”
The group has members from Warnham, Rusper, Kingsfold, Rowhook, Broadbridge Heath, Slinfold Parishes and North Horsham.??
Sussex Police said one of the signs was damaged on Sunday between 5.20pm and 7.20pm.
A spokesman asked anyone who saw what happened or has any information to contact police on firstname.lastname@example.org or call 101 quoting serial 1307 of 10/8.