Property due diligence:
the boundary agreement a buyer never saw

A clean-looking title plan can create false confidence. HM Land Registry plans normally show only a general boundary, while historic agreements, deeds, occupation and physical features can determine where the legal line actually lies.

White v Alder: the agreement before the purchase.

In late October 2005, the then owners of two neighbouring properties—Willow Cottage and The Old Stores—made an oral agreement about the location of their boundary. The agreement was later recorded in writing.

Mr White bought Willow Cottage in November 2005. Mr and Mrs Alder acquired The Old Stores at around the same time. More than a decade later, Mr White demolished part of the boundary wall and built an extension. The Alders alleged that its foundations trespassed over the line established by the earlier agreement.

The dispute reached the Court of Appeal in White v Alder [2025] EWCA Civ 392. The question was whether the earlier boundary agreement could bind successor owners and, if so, whether a later owner had to know about it.

What the Court of Appeal decided.

The Court of Appeal dismissed Mr White's appeal in April 2025. It held that an agreement which identifies the position of an uncertain boundary can bind successors in title by itself; the successor does not have to know of the agreement.

The Supreme Court refused permission to appeal on 10 October 2025 because the application did not raise an arguable point of law. That refusal leaves the Court of Appeal decision standing. It is not, however, a separate Supreme Court judgment endorsing every part of the reasoning.

The distinction between a boundary agreement and a transfer of land matters. HM Land Registry explains that an agreement which clarifies an unclear boundary is generally presumed not to transfer land. An arrangement which deliberately transfers land is different and must satisfy the relevant legal formalities. The document, history and parties' intentions therefore need careful legal analysis.

Why the Land Registry title plan is not a survey.

HM Land Registry's current guidance says the red edging on a title plan shows the general extent of the registered land. It does not normally identify the exact legal boundary, identify who owns a wall or fence, or provide dimensions from which the legal line should be scaled.

A reliable review reads the title plan together with the register and every deed, transfer or lease referred to in it. It then compares those documents with a measured survey, the physical boundary features and the pattern of occupation.

That comparison can reveal:

• a wall, fence or hedge that does not follow the assumed title line;
• an extension, access, parking space or service crossing neighbouring land;
• historic rights, covenants or maintenance obligations in an older deed;
• an informal arrangement which may have acquired legal significance; or
• a gap between the land needed for a proposed scheme and the land actually controlled.

Planning permission is a separate test.

Planning control concerns whether development is acceptable in the public interest. It does not decide private ownership or remove restrictive covenants and other private rights. A planning permission can therefore exist for a scheme that the applicant cannot lawfully build without resolving a title, access or boundary issue.

The reverse can also be true: ownership of the land does not establish that its present use or development is lawful in planning terms. Acquisition due diligence should reconcile the planning drawings, red-line application site, approved access and operational requirements with the legal title and physical site.

This is particularly important where value depends on a narrow access, a side extension, parking layout, servicing route, change of use or redevelopment close to a boundary.

What a property intelligence brief should test.

A property intelligence brief is not a replacement for conveyancing or a building survey. Its role is to connect the information that is often reviewed in separate workstreams and identify the questions that affect the commercial decision.

1. Legal record. Review the register, title plan, lease and referred deeds with the solicitor, including easements, covenants, restrictions and boundary material.
2. Physical reality. Compare mapped boundaries with walls, fences, buildings, access, parking, services and the land actually occupied.
3. Planning position. Check permissions, approved plans, conditions, lawful-use evidence, enforcement history and whether the consent relies on land outside the title.
4. Occupation. Identify tenants, licensees, shared areas, informal users and anyone exercising rights over the property.
5. Regulatory exposure. Test licensing, building-control, fire-safety, environmental and business-rates issues relevant to the intended use.
6. Commercial dependence. State which risk could stop the transaction, reduce value, delay delivery or make the intended operation impractical.

The output should be a decision document: confirmed facts, unresolved questions, evidence required, responsible adviser and a clear action before exchange, completion or design commitment.

Turn each red flag into a transaction decision.

Not every discrepancy should stop a purchase. The response may be a targeted enquiry, historic document search, measured survey, legal opinion, boundary agreement, formal transfer, determined-boundary application, insurance or a change to the design. In other cases, the right response may be a condition to completion, price adjustment or withdrawal.

The important step is to quantify the dependency before the buyer is committed. If the development value assumes use of a strip of land, access through a gate or construction hard against a wall, “the title looks fine” is not a sufficient conclusion.

White v Alder is a boundary case, but its commercial message travels further. Property risk often sits in the mismatch between records, physical use and the intended plan. That mismatch is where a focused intelligence review adds value.