Trespass to land is a civil wrong and as such the police have no jurisdiction. Under common law, the landowner has a right to re-entry on the land, however the ejection of the trespasser is fraught with danger for the landowner. Initially, the landowner should ask the occupier to leave the land and if he/she does then all is well. The problems start however, if he/she refuses to leave the land.
The owner of the land could commit several criminal offences if he forcibly removes the trespasser and his/her property from the land. The best and safest course of action is to obtain a court order, which if breached may then turn into a criminal matter.
If the police do attend an incident such as this, they are merely there as observers for any possible criminal offences committed by either party. The police cannot assist in the removal of the trespasser or their property from the land in question.
The police do have some powers against two or more trespassers if damage has been caused, or there are more than six vehicles on the land.