A report today by the law reform and human rights organisation, Justice, tackles the important issue of third party interventions in the Supreme Court.

Last year almost a third of House of Lords cases involved such interventions. “To Assist the Court”  provides a valuable insight to the history and current practice. 

The submissions by third parties are often valuable. After all, if the points being argued have constitutional importance, they are bound to have implications beyond the interests of the parties themselves. Furthermore, even within our adversarial system, the Court may be assisted by different perspective. As Sedley LJ has said in the Court of Appeal, a third party intervention can avoid “the polar positions adopted, as tends to happen in litigation, by the parties and instead reasons by degrees.”

However, the practice and procedures relating to interventions has developed largely in an ad hoc way. Justice suggests that at a time when our highest court is undergoing modernisation and procedural reform, there is an opportunity for setting out clearer guidance in this area as well.

 Justice makes 9 recommendations for interventions in important cases: 


The Court Service increase its efforts to ensure greater transparency and information on its website concerning pending cases, so that potential interveners can identify at a sufficiently early stage cases that may be appropriate for intervention. The information should include a summary of the issues raised by the case and contact details so that prospective interveners can obtain the claim form or grounds of appeal electronically.

The European Court of Human Rights should similarly identify on its website when states parties are granted leave to intervene in cases involving other Council of Europe member states.

If the Treasury Solicitor’s Department is to maintain its policy of neither opposing nor consenting to third party interventions, it should ensure that the policy is applied consistently. In particular, the Department should not unreasonably or instinctively oppose applications to intervene at hearing by way of oral submissions.

The permission of the court should always be a requirement for a third party intervention. However, if an intervener was granted leave to intervene in the court below, there should be a presumption when leave to appeal is granted that any intervener will also be granted further leave to intervene at the same time.

An applicant for permission to intervene should be obliged to show that they have written to the parties for their consent. However, the courts should not refuse to consider an application for leave to intervene solely on the basis that the parties have failed to respond to the intervener’s request for consent.

There should be no fee for applying for leave to intervene in the public interest, regardless of the level of court at which the application is made.

The courts should continue their now-established practice of allowing interventions in the public interest. However, we recommend against seeking to define ‘the public interest’. If a definition is thought necessary, it should be as broad and inclusive as possible.

When a court grants leave to intervene, there should be a presumption in favour of granting the intervener leave to make both written submissions and, where represented by counsel, oral submissions.

The courts should maintain the general rule that interveners should bear their own costs, but should not be liable for the costs of other parties.