The Court of Appeal found in R. (on the application of Mott) v Environment Agency [2016] EWCA Civ 564 that a decision significantly to reduce the number of salmon the Claimant was permitted to catch was not irrational. However, it did breach his property rights under Article 1 of Protocol 1 (“A1P1”) to the European Convention on Human Rights because he was not compensated. This case confirms previous case law on the margin of appreciation to be given to expert decision makers, and sets out a helpful summary of those cases in the reasoning on that point. This case is particularly interesting as it states that an interference with a person’s “control” of their property on environmental grounds does not necessarily mean that interference can be made without compensation and the principle of “fair balance” will apply.


The Claimant, Mr Mott, had a leasehold right to fish for salmon in the Severn estuary. Since 2012, the Environment Agency (the “Agency“) has imposed an annual limit on the number of salmon which could be caught with a putcher rank (an ancient method of fishing). The Agency’s decision was largely based on a report it received from The University of Exeter’s College of Life and Environmental Sciences (the “Report“). The Agency considered the change necessary in order to protect salmon fisheries in the River Wye. As a result of the change, Mr Mott’s permissible catch was reduced by around 95%.

Mr Mott raised a collateral challenge to the conditions imposed upon his licence limiting his catch. The High Court held that the decision to impose the limits was unlawful as it was irrational, and because it unlawfully interfered with Mr Mott’s A1P1 rights. The Agency appealed to the Court of Appeal.


The Court of Appeal considered two key questions:

  1. Was the Agency’s approach irrational?
  2. In the context of A1P1, was the interference with Mr Mott’s right to catch salmon a “deprivation” or a “control”, and if the limit was imposed without compensation, was it disproportionate and therefore unlawful?

The Court found, on the first question, that the decision to impose a catch limit was not unlawful for being irrational. Judges should have regard to the expertise of expert regulatory bodies, although those bodies must still provide a clear explanation of their decision to the Court. In this case, the evidence was not easily accessible, and did not counter criticisms that Mr Mott had given about the Report. The Court acknowledged that it was, therefore, understandable that the first instance judge had sought to make an educated guess about a number of matters. However, he had erred in doing so. On the facts, the Agency had made its decision against an unchallenged assessment by the Agency as to the risk to the River Wye, and a background assumption (about salmon returning to their river of origin to spawn) on which there was scientific consensus.

Ultimately, the Court found, having summarised the case law on this issue, that judges must give sufficient weight to the nature of the exercise, and expertise of the relevant body. It should be cautious to impugn that body’s decisions and, in particular, its “educated prophecies and predictions for the future“.  Additionally, the Court warned against judges engaging in a detailed examination of the merits of an approach, and accuracy of calculations based on models, in judicial reviews of a scientific topic.

On the second question the Court found that, in this case, a breach of A1P1 could only be prevented by payment of compensation because of the extent of the limit that had been imposed on Mr Mott’s right to catch salmon, and the way in which it had been apportioned. Strasbourg jurisprudence states that where there is no formal expropriation, the Court must look beyond appearances and investigate the realities of the situation. There is a deprivation where the owner is deprived of all meaningful use. Given that the restrictions eliminated 95% of the benefit Mr Mott had, this interference was closer to “deprivation” than to “control”.

Additionally, “even if the interference is only a “control”it does not follow that because it is made on environmental grounds that any restriction can be made without compensation.” The Court briefly analysed R (Trailer & Marina (Level) Ltd) v Secretary of State for the Environment [2004] EWCA Civ 1580 in which it was said that compensation would be required to redress the balance, and avoid a breach of A1P1, where the state could not properly take the view that the benefit to the community outweighed the detriment to the individual. This is the “fair balance” test which must be applied. However, in Trailer & Marina the A1P1 argument was only considered in principle. Relevantly, on the facts of the current case, there was no evidence that the Agency had considered the extent of the effect on Mr Mott and his livelihood. The way in which the Agency had calculated the levelling of catches meant that there was a lower effect on those whose rights were less extensive, and who may have only used their rights for leisure, and a higher effect on Mr Mott (who had more extensive rights). This meant that, in the circumstances, compensation would be required in order to prevent a breach of Mr Mott’s A1P1 rights.


This case gives a helpful summary of case law on the margin of appreciation afforded to expert decision makers, particularly where the decision is scientific, technical and/or predictive in nature. It is also interesting because, although the decision to impose a limit was ultimately found not to be irrational (because of the deference shown to the Environment Agency’s decision), the limit was nonetheless a breach of A1P1 rights because Mr Mott was not compensated. This highlights the effectiveness of an A1P1 argument to claimants particularly in the face of the high hurdle of the typical judicial review heads of claim. It is particularly interesting that the Court considered the test for compensation in the event of interference with an individual’s “control” of property under A1P1, because of the finding of “deprivation” on the facts of the case. The indication from this judgment appears to be that the Court will assess whether a “fair balance” has indeed been struck if there is an interference amounting to a “control” of use, and that it will be willing to find that compensation is required to assist in fixing any imbalance.