Any animal found on a public highway should be reported to the police. If you feel there’s an immediate danger to road users call 999, otherwise call the non-emergency line on 101.
You can report cruelty or an animal in distress to the RSPCA.
Most horse abandonment and fly-grazing cases are a civil matter and would be up to the land owner to resolve. The council does not have any statutory obligations to provide an emergency response, and we have no specialist equipment, expertise or resources to deal with loose horses.