Ad Medium Filum: Solving Boundary Issues Beside Roads and River

A not uncommon problem faced by property owners can arise when a thin strip of land, between the registered title and a highway or stream,  appears unregistered. These gaps can delay development or complicate access and service routes. One potential legal remedy lies in the legal presumption known as “ad medium filum”.

What Is Ad Medium Filum?

Ad medium filum literally means “to the middle line”. It is a legal principle that assumes a landowner whose property borders a highway or non-tidal watercourse owns the land up to the centreline of that feature, even if it doesn’t appear in their title plan.

This applies to:

• Public or private roads
• Non-tidal rivers or streams

In the case of highways, the highway authority may be responsible for maintenance of the adopted road, but that doesn’t necessarily mean they own the subsoil underneath the adopted road. That can belong to the adjoining landowner.

When Does It Apply?

The presumption applies unless clear evidence shows otherwise, such as title deeds or historic plans that exclude the land. It can be rebutted by:

• Specific wording in previous conveyances
• Clear plan boundaries
• Known ownership by a third party (e.g. the highway authority)

Why It Matters

For developers or landowners, unregistered boundary strips can:

• Obstruct access
• Complicated utility installation
• Delay planning or financing

Using the ad medium filum, you may be able to register the unclaimed land with HM Land Registry, typically gaining possessory title, which can be supported by indemnity insurance.

How to Proceed

• Review your title and deeds – Check for evidence supporting ownership to the midpoint.
• Gather supporting documents – Photos, historic plans, or statutory declarations.
• Submit an application to the HM Land Registry for first registration.
• Insure if needed – A Possessory title may still benefit from legal cover.

Our Support

Ashtons Legal can:

• Review and assess the merits of a potential claim
• Prepare the necessary legal documentation
• Submit and manage the registration process
• Advise on indemnity insurance and risk management

In Summary

If your land borders a road or watercourse and the boundary seems unclear, ad medium filum could offer a legally valid route to secure ownership of missing land. Our property team is here to help clarify your position and strengthen your title.

Contact our Property Disputes solicitors today

Our specialist Property Disputes team has extensive experience in resolving boundary disagreements and advising on the enforceability of historical agreements. Whether you’re a landowner, developer, or buyer, we can help you understand your rights and options.

If you have any questions regarding the points raised in this article, please get in touch with our specialist Property Litigation team by using our online enquiry form or calling 0330 404 0738.