Curzon Park: certificates of alternative development
Secretary of State for Transport v Curzon Park Limited and others [2023] UKSC 30 concerns certificates of appropriate alternative development, usually called CAADs, in compulsory-purchase compensation.
The Supreme Court drew an important distinction: another site’s certificate is not a real planning permission, but the information behind it may still be relevant evidence.
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- Neutral citation
- [2023] UKSC 30
- Court
- Supreme Court of the United Kingdom
- Judgment date
- 10th August 2023
- Judge
- Lord Kitchin, Lord Sales, Lord Hamblen, Lord Leggatt and Lady Rose
Four neighbouring sites acquired for HS2
The sites were acquired for the Birmingham railway terminus. Their owners sought certificates identifying development which could reasonably have been expected to receive permission in the statutory circumstances without the acquisition scheme.
Each certificate proposal included student accommodation. The dispute concerned whether the decision-maker could consider the other sites’ CAAD applications or decisions when assessing the appropriate alternative development of one site.
The Court of Appeal had excluded those applications and decisions altogether. The Supreme Court rejected that absolute exclusion.
A certificate does not authorise construction
A CAAD assists the compensation exercise. It does not grant permission to develop the land, and the application for it is not automatically evidence that its owner would have submitted an identical planning application in reality.
Granting a certificate for student bedrooms on one site therefore did not itself consume a fixed amount of planning need and leave only the balance for neighbouring sites.
The Secretary of State’s earlier argument treating the certificates as equivalent to actual permissions was not revived in the Supreme Court and could not be sustained.
Relevant evidence need not be ignored
The material submitted with another CAAD could nevertheless illuminate circumstances known to the market at the relevant valuation date. It might assist an assessment of alternative sites, cumulative effects or incompatible neighbouring development.
The statutory assumption that the acquisition scheme had been cancelled did not require every real-world source of evidence connected with it to be erased.
The distinction is between using the evidence for what it can establish and pretending that a certificate is an actual permission. The relevance and weight of the material remain matters for the decision-maker within the statutory framework.
The valuation date limits the exercise
The court rejected speculation about hypothetical permissions supposedly granted between the assumed cancellation date and the valuation date. The assessment had to use the prescribed assumptions and the circumstances known to the market at the relevant date.
It also distinguished ordinary hope value from the stronger statutory assumptions applicable to appropriate alternative development. Read Spirerose for the earlier authority on not converting probability into certainty without a statutory basis.
A limited appeal, not a final compensation award
The Supreme Court allowed the appeal to the limited extent explained in its judgment and restored the Upper Tribunal’s declaration on the preliminary issue.
It did not fix the compensation payable for each site or decide that all the accommodation in the certificates would actually have been permitted. A present compensation claim requires the applicable version of the statutory code to be checked, rather than assuming that every provision quoted in this judgment remains unchanged.
Read Curzon Park
The complete Supreme Court judgment is available to Gold Members.
Curzon Park Case Law Page Updated: 12th September 2026