Horse welfare officers and farmers have welcomed new laws which are aimed to stamp out fly-grazing.
Horses can be left in terrible conditions or cause damage to crops and fences after being dumped illegally or tethered to one spot by irresponsible owners.
But the Control of Horses Act came into force on Tuesday and gives greater power to landowners.
Previously landowners had to wait 14 days to dispose of the horses through a sale or auction.
Thanks to new laws, landowners can immediately take the horses to a place of safety, notifying police within 24 hours. If no owner is identified within four working days, the horses can be sold or re-homed to charities.
Field officer for World Horse Welfare in West Norfolk, Jacko Jackson, has welcomed the new act.
He says 25 per cent of his workload is down to fly-grazing and says horses are tethered along the droves in Wisbech.
Mr Jackson said: “It is not too bad at this time of year providing they move the tether, but problems start occurring when the animal can’t reach food and water. A lot of these horses don’t have access to water.
“They also have a worm burden as they are eating and defecating in one area.
“Quite often under the old act, they would wait until the landowners have put the horses up for auction and buy them back for a fraction of the price.
“We hope it will deter people from doing it.”
World Horse Welfare along the CLA and NFU have been campaigning for change. CLA East Regional Director Ben Underwood said: “Fly-grazed horses can damage land, crops and fencing, restrict space for livestock and cost money to provide for their welfare and safety. It has been very difficult, time consuming and expensive for landowners to deal with these situations but from Tuesday they can take swifter action to resolve the problem.”
MP Steve Barclay said: “It is great news for farmers and councillors as it means they will now have the tools they need to rescue horses that are being illegally fly-grazed. It is a real issue in our area and it causes problems for landowners and even drivers, if the horses get loose. Many of the horses are abandoned and neglected, which is distressing.”