I have set out below an introduction to trespass to land which I hope you may find helpful.
NOTE: The information below is an introduction to this complex field. It is not intended to replace specific advice and, necessarily compresses some legal issues for ease of understanding .
Where trespassers enter onto land and occupy it, the law allows a summary procedure to recover the possession.
The procedure can be used where the trespassers entered or remained on the land (eg where a licence to occupy has been terminated) without the permission of the person who has a right to possession. Note that this means a tenant can apply to recover possession against a trespasser.
However, the summary procedure cannot be used by a landlord against tenants or sub-tenants even if the tenancy has terminated.
Why use the Court procedure at all? Because a landowner who attempts to evict trespassers without a Court Order risks allegations of a breach of the peace and may face civil or criminal sanction. (Also, better to let a professional who is used to physically taking possession take the strain - see below).
Getting an Order
Claims are usually begun in the County Court for the area where the land is located. The High Court is only appropriate where there are complex issues of fact, or points of law of general importance to be considered.
It is not necessary to find out details of the Defendants: indeed it is better not to know because the Claim can then be addressed to "Persons in occupation whose identities are not known to the Claimant” - whereas if you find out names you have to name and serve those people specifically.
Service is achieved by attaching the papers to some prominent place on the land (eg by using a stake in the ground); and inserting through letter boxes/doors eg of each caravan.
Where the land is not residential (eg open field, car park or commercial land) only two clear days service is required. This can be shortened if there is need eg where the trespassers threaten violence against the Claimant or threaten/cause serious damage to the property or other property in the locality eg by setting fires.
The matter will come before a (Deputy) District Judge who will rely on written evidence: the Claimant will have to prove title to the land. If a substantive Defence is filed (eg disputing ownership, then directions will be given - but where that is expected the summary procedure is not suitable and should not be used). Where there is no Defence the usual order is possession forthwith.
Enforcing the Order
Once you have the order you can apply to the County Court for a warrant to be executed by the Bailiff.
However, depending on the circumstances it may be appropriate to transfer the order to the High Court for enforcement using the High Court Enforcement Officers (formerly known as the Sheriff). The HCEO will have the know how and resources to remove the trespassers, and a relationship with the local police where trouble is expected. It is usual to give a short period of time - say 24 hours - to leave. This is not a requirement of law and possession can be enforced forthwith where is is desirable to do so.