Background

The International Labour Organisation (ILO) is a United Nations specialised agency focused on setting international labour standards, which it does through conventions and recommendations. It mostly operates on a tripartite basis, with the views of employees’ representatives, employers’ representatives and its 187 member states having equal weight.

The ILO’s Committee of Experts, which makes observations on member states’ reports on compliance with conventions, has for decades expressed the belief that ILO Convention No. 87 on freedom of association and protection of the right to organise contains a right to strike. This right is not explicitly stated in the Convention, the text of which was agreed on a tripartite basis in 1948. The Committee of Experts is composed of legal experts and is not a tripartite body. The Committee on Freedom of Association, which is a tripartite ILO body dealing with complaints relating to alleged infringements of trade union rights, such as its recent case on the UK Supreme Court’s decision in the Deliveroo case (in which we acted and wrote about here), has generally agreed with the Committee of Experts in this regard.

In 1994, the ILO Employers’ Group objected to this interpretation of the Convention and more broadly to the idea that these bodies could provide authoritative interpretations of conventions. This escalated dramatically in June 2012, when the Employers’ Group representatives walked out of the International Labour Conference (the ILO’s highest decision-making body) in protest.

The Employers’ Group’s non-participation has affected the ILO’s work, and negotiations to resolve the issue were not successful. As a result, in November 2023 the ILO’s Governing Body referred the following question to the International Court of Justice (the principal judicial organ of the United Nations), for an Advisory Opinion: is the right to strike of workers and their organisations protected by the Convention?

What did the ICJ decide?

The ICJ’s Advisory Opinion was issued on 21 May 2026. By a majority of ten judges to four, the Court found that the Convention does contain a right to strike.

The Court first acknowledged that the Convention does not explicitly include a right to strike. However, this didn’t mean the right was automatically excluded. The Convention is silent on the matter and does not explicitly exclude a right to strike. It provides that workers (and employers) have the right to create and join organisations for the purpose of furthering and defending their interests, including to organise their “activities” and “programmes” to pursue that purpose.

“Activities” and “programmes” are undefined, but the ICJ found that strike action was capable of being an “activity”. The Court defined a strike as “an activity consisting of a temporary work stoppage or slowdown wilfully effected by one or more groups of workers with a view to enforcing or resisting demands or expressing or supporting grievances”. This includes both strikes, as understood in a UK context, and work stoppages short of strikes, such as “go slow” or “work to rule” actions.

Having found that the Convention could contain a right to strike, the majority of the Court found that it did contain this right on the following grounds:

• The right to strike is in line with the object and purpose of the Convention: to guarantee freedom of association as a means of improving labour conditions and achieving sustained progress.
• This is also reflected in other relevant rules of international law in the twin covenants of 1966: the International Covenant on Civil and Political Rights and the International Covenant on Economic, Social and Cultural Rights.
• Other supplementary means of interpretation either support the right to strike or are inconclusive on the topic. This includes the statements of ILO supervisory bodies such as the Committee on Freedom of Association and the Committee of Experts, to which — contrary to the views of the Employers’ Group — the ICJ said it could give “great weight” in a similar way to bodies like the UN Human Rights Committee.

The majority of the Court declined to determine the precise content, scope or conditions for the exercise of the right to strike, but held that such a right did exist in the Convention.

The dissenting judges disagreed with the majority’s approach to treaty interpretation, arguing that the majority was reasoning backwards from the aim they wanted to achieve, and that there was no clear intention of the drafters of the Convention to include a right to strike.

What does this mean for employers in the UK?

The current government is undeniably more supportive of unions than previous Conservative governments. For example, in October 2024, Labour withdrew the previous government’s submission to the ICJ arguing against the right to strike. The legal requirements for a valid strike have also recently been significantly loosened by the Employment Rights Act 2025.

However, the opinion does not have any immediate legal consequences in the UK, as the Convention has not been incorporated into UK law.

The ICJ opinion may nonetheless be relevant to future industrial action cases in the UK. This is because it is an opinion to which the European Court of Human Rights must have regard and, in turn, UK courts must have regard to decisions of the European Court of Human Rights when making decisions in a manner that is compatible with the Human Rights Act. This is particularly the case as the ICJ opinion may well now trigger assessments within the ILO system of the precise content, scope or conditions for the exercise of the right to strike, with those assessments also being matters to which the European Court of Human Rights may have regard.

However, whilst there is no express right to strike in the UK and there are no plans to introduce one, laws across the UK provide immunity for calling and participating in strikes, so long as that takes place in accordance with legally prescribed rules. Further, in its recent decision in Mercer, the UK Supreme Court adopted the terminology of a ‘right to strike’ for the first time, meaning that the ICJ has gone no further than the point to which the UK Supreme Court appears to have now advanced in any event.

We will therefore have to wait and see whether this opinion motivates UK unions or employees to bring litigation challenging existing restrictions on strike action or trade union activities. However, it seems unlikely that such litigation would be successful on that basis alone, even if the decision might encourage them that the overall direction of travel in terms of a ‘right to strike’ is in their favour.

Right to Strike under ILO Convention No. 87, Advisory Opinion of 21 May 2026 – read the opinion here.