The Supreme Court has handed down its decision in a long-running case concerning whether protections against detriments short of dismissal for engaging in trade union activities are extensive enough to comply with the UK's obligations under the European Convention on Human Rights (ECHR) (Secretary of State for Business and Trade v Mercer).

The case concerned a charity worker who acted as workplace representative for a trade union and was involved in organising a series of strikes. After she was suspended, she brought Employment Tribunal (ET) proceedings alleging that the charity had subjected her to a detriment for taking part in trade union activities, contrary to Section 146 of the Trade Union and Labour Relations (Consolidation) Act 1992. The charity claimed that industrial action was not an activity protected by Section 146.

The ET found that Section 146 did not apply to industrial action and was therefore incompatible with Article 11 of the ECHR, which enshrines the rights to freedom of assembly and association, including the right to join a trade union. However, it concluded that Section 146 could not be interpreted so as to achieve compatibility with Article 11. This decision was subsequently reversed by the Employment Appeal Tribunal.

The case then came before the Court of Appeal, which restored the ET's decision. While the absence of protection against detriments short of dismissal might put the UK in breach of Article 11, interpreting Section 146 as if it conferred such protection would amount to 'impermissible judicial legislation', rather than interpretation. In declining to grant a declaration that Section 146 was incompatible with Article 11, the Court cited the lack of a specific statutory provision that was incompatible and the complexity of the policy choices involved.

The Supreme Court agreed with the Court of Appeal that an interpretation of Section 146 that complied with Article 11 was not possible. However, it noted that Section 146 'has the implicit effect of legitimising sanctions short of dismissal' in response to strike action. Concluding that it was appropriate to make a declaration of incompatibility, the Court noted that it would be for Parliament to decide whether and how to legislate to protect against such sanctions.