Government concedes that first ever IROPI opinions on a local plan were unlawful

The decision marks the second time the Secretary of State has withdrawn an opinion on the IROPI, which is thought to be the first instance of the test being applied to a council’s local plan.

The dispute centres around Portsmouth's local plan, which proposes housing in the adjacent to and within the Portsmouth Harbour Special Protection Area (SPA).

As part of the plan preparation process, the council commissioned a Habitats Regulations Assessment (HRA) which concluded the development was likely to have adverse effects on the integrity of some protected habitats in the harbour.

However, the HRA also concluded that there were imperative reasons of overriding public interest (IROPI) to adopt a version of the draft local plan which included the development.

An IROPI exception is a legal test used to justify a plan or project that would otherwise be restricted by the Habitats and Species Regulations 2017. It is typically seen in cases involving national infrastructure projects and has never previously been relied on for the adoption of a local plan, according to lawyers representing the council.

In October 2024, the council invited the Secretary of State to provide an opinion on whether the reasons relied on by the council for progressing draft Policy PLP3, notwithstanding its implications for a European site, are considered to be IROPI.

On 28 February 2025, the Secretary of State notified the council of her opinion that the reasons relied on by the council did not constitute IROPI. The substantive part of the opinion was contained in just three short paragraphs.

The council then wrote a pre-action protocol letter to the Secretary of State, complaining that the letter failed to provide adequate reasons for her opinion.

She later withdrew her opinion, admitting that the decision to issue it had been unlawful because she had failed to give adequate reasons for her opinion that each of the grounds relied on by the council individually and cumulatively did not constitute IROPI.

She also said that her opinion was based on flawed reasoning and failed to have regard to obviously material considerations - and was therefore irrational.

A second much more detailed opinion on the IROPI was then issued five months later, again concluding that IROPI had not been established.

Portsmouth responded by issuing a second pre-action protocol letter on 7 October, which resulted in the Secretary of State withdrawing their second opinion.

The Secretary of State made the second withdrawal on the basis that they had failed to have regard to mandatory material considerations namely the proposed mitigations for construction impacts.

They also said that their opinion failed to give any or any adequate reasons for concluding that the city council’s proposed mitigation measures for construction impacts and recreational pressure were ineffective to rule out adverse impacts at the Plan-level.

Robert Walton KC of Landmark Chambers and Toby Fisher of Matrix Chambers are promoting the plan for the council.

The council is continuing work to prepare its local plan for submission next year to meet Government deadlines.

Adam Carey