Drawing the Line: Court of Appeal Rules on Successor Obligations in Boundary Disputes (White v Alder [2025])

The 2025 Court of Appeal decision in Darren White (“Mr White”) v. Michael Alder and Sheila Alder (“the Alders”) has brought significant attention to the legal position of successors in title with respect to pre-existing Boundary Agreements.

In this case, the Court of Appeal addressed a pivotal issue concerning the binding nature of Boundary Agreements on successors in title, and whether such agreements are enforceable against new property owners who had no knowledge of them at the time of acquisition. As a solicitor within the Litigation team, I have been closely reviewing the potential impact of this ruling, particularly in relation to the rights and obligations of new property owners.

What is a Boundary Agreement?

A Boundary Agreement is an Agreement, either written or implied, between neighbouring landowners about the position of the Boundary separating their properties. The key concept is that parties are not trying to transfer ownership of land but are simply agreeing on where the dividing line should be treated as being.

Aspin LJ, who gave the leading judgment in White v Alder, described two types of Boundary Agreements.

• First, as a transfer of land from one neighbour to another, which are subject to the formalities necessary for the transfer of land.
• The second type is an agreement (Boundary Demarcation Agreement), the purpose of which is to define a previously unclear or uncertain Boundary, even if they include the conscious or unconscious transfer of a trivial amount of land.

The case of White v Alder falls within the scope of a Boundary Demarcation Agreement.

Circumstances resulting in the dispute between Mr White and the Alders

In or about November 2005, the Alders and Mr White each purchased a property, resulting in them becoming neighbours. Before the purchase, the predecessors in title (“previous owners”), had formally agreed a Boundary line. This Boundary Agreement was not disclosed to, nor known by, Mr White at the time he acquired his property.

Several years later, Mr White commenced building works which arguably encroached on the Alders’ land. As a result, the Alders initiated proceedings, in which they were ultimately successful. Mr White subsequently appealed this decision, arguing that he should not be bound by the prior Boundary Agreement due to his lack of knowledge of its existence. The matter proceeded to the Court of Appeal.

The issue before the Court of Appeal was whether Mr White was bound by the Agreement between the previous owners and whether knowledge of the agreement is a necessary condition for its binding effect.

Judgement

Multiple cases were examined before judgement was delivered. These cases included Gibson v New & Anor [2021] EWHC 1811 (QB), Neilson v Poole (1969) 20P&CR 909, Joyce v Rigolli [2004] EWCA Civ 79 and Haycocks & Anor v Neville & Anor [2007] EWCA Civ 78.
After careful consideration, the Court of Appeal dismissed Mr White’s appeal, determining that Boundary Agreements are binding on successors irrespective of their knowledge of the Agreement.

Aspin LJ explained the following in the judgement:

“Such an Agreement has proprietary effect and, as a result, also binds successors in title. It does so because of its very nature. It defines and delineates the Boundary between the properties as from the root conveyance or transfer. Such an Agreement is, of its very nature, a delineation of the property transferred or conveyed and is so for all purposes. As no one is able to transfer or convey more than they own, such an Agreement effectively “binds” successors in title whether or not they have knowledge of it. It does so because it defines what they purchase”.

The main points to take away are as follows:

1. Boundary agreements bind successors in title.
2. When two property owners make an Agreement that defines where the Boundary line is (irrespective of when the Agreement took place), that Agreement defines the land itself and what it includes. This means anyone who buys land after this, even if they were not aware of the pre-existing Agreement, is automatically bound, as the Boundary Agreement defines what they have purchased.
3. Knowledge of the Agreement is not a necessary condition for its binding effects.
4. Boundary Agreements are put in place to reduce disputes and clarify ownership.
5. Failing to adhere to a Boundary Agreement may result in proceedings against you.

Legal Importance

This case may set a precedent for how courts interpret the binding nature of Boundary Agreements on successors in title, particularly in relation to pre-existing Agreements.

It provides further clarification on the extent to which Boundary Agreements can impact future owners, whilst reinforcing the importance of raising enquiries and the need for legal certainty when purchasing land.

Like Mr White, many people purchase land and start building works without considering or having knowledge of the Boundary line or pre-existing Agreements. Boundary uncertainty or encroachment can often give rise to disputes between neighbours.
White v Alder is a crucial reminder of why it is important to obtain advice at early stages.

Need advice on a Boundary dispute?

Contact our Litigation team [email protected] or 01732 770660. The team at Warners are available to assist clients with resolving Boundary disputes and offer advice to new and current property owners on their legal obligations, and rights concerning Boundary Agreements.

This article is for general information only and does not constitute legal or professional advice. Please note that the law may have changed since this article was published. We do not accept responsibility or liability for any actions taken based on the information in this article.