Stand up for your interest: interested parties and standing to apply for a variation of an Aarhus Convention cost cap

The Aarhus Convention has for some time now been a welcome benefit to claimants involved in environmental litigation ensuring that there is ‘inexpensive’ access to justice in such cases and helping (as far as possible) to ensure an equality of arms. This has been of particular benefit to individuals and local interest groups looking to challenge planning applications in their area, without the threat of incurring potentially hundreds of thousands of pounds worth of legal costs if their challenge is unsuccessful.

However, the Aarhus Convention has not always been of a benefit to interested parties (such as the developer with the benefit of a planning permission, or a local authority wishing to uphold an appeal decision) who want to respond to such a claim but who fear not getting any of their costs back if an Aarhus costs cap is in place. Defendants have always had the ability under the Civil Procedure Rules (‘CPR’) to apply to increase a claimant’s Aarhus costs cap if they feel that it is unjust, but what about interested parties? This point was considered in the case of R (Bertoncini) v London Borough of Hammersmith and Fulham and Kendall Massey CO/3213/2019 [2020] EWHC where His Honour Judge Bird (sitting as a High Court Judge) held it would be unjust if interested parties had no standing to apply to vary the cap on costs.


The United Nations Economic Commission for Europe (UNECE) Convention on Access to Information, Public Participation in Decision-making and Access to Justice in Environmental Matters (‘Aarhus Convention’) requires contracting states to ensure that the costs of making certain environmental challenges in court are not prohibitively expensive.

The Civil Procedure Rules (‘CPR’) recognise this requirement through a specific costs regime for Aarhus Convention claims (CPR 45.41-45.55).

CPR 45.42 ensures that a claimant’s costs liability is capped at £5,000 (for individuals not claiming on behalf of a business or other legal person) or £10,000 (in other cases).

The Civil Procedure (Amendment) Rules 2017 (SI 2017/95) have allowed the courts more discretion to remove or vary the cost limit. This is the case if the court is satisfied that:

  1. To do so would not make the costs of the proceedings prohibitively expensive for the claimant; and
  2. In the case of a variation which would reduce a claimant’s maximum costs liability, or increase that of a defendant, without the variation the costs of the proceedings would be prohibitively expensive for the claimant.
    (CPR 45.44(1)-(2))


In 2019, Waksman J in the High Court (‘Court’) refused permission for the Claimant to proceed with a judicial review application. The Court held the claim was an Aarhus Convention claim under CPR 45.41 but ordered the £5,000 cap on the Claimant’s costs liability be increased to £20,000 following submissions on this point from the Defendant and the Interested Party.

The Claimant renewed the application, and the Court was posed with two matters to address:

  1. To determine whether an interested party has standing to apply for a variation of a costs cap in an Aarhus Convention claim; and
  2. To reconsider the order made by Waksman J.


HHJ Bird sitting in the High Court held that an interested party does have the standing to apply for a variation of a costs cap in an Aarhus Convention claim.

HHJ Bird cited Campaign to Protected Rural England v Secretary of State for Communities and Local Government [2019] EWCA Civ 1230. In this case it was held that although CPR 45.44(5) and 45.5(7) made no specific references to interested parties, their costs could be covered up to the cap. Coulson LJ said that CPR 45.4.3 limits the costs exposure to the claimant but it does not specify to whom the claimant may be paying the costs up to the cap limit. The obvious answer is: any defendant or interested party who is otherwise entitled to their costs.

As an interested party is subject to the Aarhus costs cap, HHJ Bird held it would be “unjust” (paragraph 10) if the said party had no standing to request the court to vary the cap. Indeed, HHJ Bird stated “the absence of any express requirements in respect of an application by an interested party should not be read as a ban on all applications by interested parties”.

HHJ Bird therefore held the costs cap should be maintained at £20,000 as Waksman J had previously ordered, as it “would not render the proceedings prohibitively expensive” (paragraph 15) for the same reasons Waksman J had previously stated.


The decision will be welcomed by interested parties and should avoid discouraging participation in environmental proceedings due concerns over a strict cost caps. The decision is in line with the principles underpinning the Aarhus Convention which promotes access to justice for environmental matters by managing the claimant’s costs exposure but with reference to the overall means of all parties to the proceedings.

This article is for general awareness only and does not constitute legal or professional advice. The law may have changed since this page was first published. If you would like further advice and assistance in relation to any of the issues raised in this article, please contact us today by telephone or email

Posted in Latest news and blog, Litigation.