Can workers be subjected to detriment for participating in lawful industrial action? The Supreme Court decision in Mercer


Does domestic law protect workers who take part in lawful strike action from detriment short of dismissal?

If not, is the UK in breach of Article 11 of the European Convention on Human Rights (‘ECHR’) (freedom of assembly and association)?

If there is a breach, can the issue be remedied under the interpretive obligation imposed by s. 3 Human Rights Act 1998 (‘HRA’), or is a declaration of incompatibility required as per s.4 HRA?

These were the questions posed to the Supreme Court in the case of Secretary of State for Business and Trade (Respondent) v Mercer (Appellant) [2024] UKSC 12 (Mercer’).

Brief Facts

Ms Mercer was a support worker in the care sector for Alternative Futures Group Ltd. She was a union representative and involved in planning lawful strike action, which she also took part in. She was subsequently suspended, during which time she received normal pay but was prevented from working and earning overtime, which she otherwise would have done.

Ms Mercer brought an Employment Tribunal claim on multiple grounds, one of which was based on s.146 Trade Union and Labour Relations (Consolidation) Act 1992 (‘TULRCA’). Section 146(1) provides that workers have the right not to be subject to any detriment if they are subjected to it for the sole or main purpose of preventing or deterring them taking part in trade union activities ‘at an appropriate time’,or penalising them for doing so. Section 146(2) defines an appropriate time as a) outside the worker’s working hours or b) within working hours where the employer’s consent is given. This, on the face of it, excludes strike activity, which necessarily takes place during working hours. The question was, therefore, whether this provision was compatible with article 11, ECHR, and if not whether any incompatibility could be remedied by the interpretive obligation imposed by s.3 HRA. 

The Lower Courts – Breach

At all stages, the courts accepted that in s.146 TULRCA the UK had, as per EJ Franey in the Employment Tribunal, ‘failed to provide effective and clear judicial protection in respect of industrial action which is part of the rights guaranteed by Article 11’.

The judgment of the Employment Tribunal did suggest that the article breached may depend upon the employer – a failure to protect workers from detriment suffered for participating in industrial action would constitute a breach of article 11 where the State was the employer. Conversely, article 13 (the right to an effective remedy before a national authority) would be breached where the State allowed a private employer to act in this way. Article 13 is not incorporated into domestic law by way of the HRA, and the breach was re-framed by the Employment Appeal Tribunal, and considered by the Court of Appeal and Supreme Court, in terms of article 11 alone.

The Lower Courts – Remedy

 The Employment Tribunal, Employment Appeal Tribunal and Court of Appeal took different views as to the extent to which s. 3 HRA could offer a remedy. The Employment Tribunal held that s.146 could not be interpreted so as to remedy the breach. The ‘grain’ of TULRCA was to distinguish between trade union activities conducted outside of working hours on the one hand, and industrial action on the other. Sections 152 and s.146 TULRCA deal with dismissal and other detriment on grounds of trade union activities, while s. 237 – s. 238A deal with dismissal for participation in industrial action. As such, interpreting s.146 so as to include industrial action would be inconsistent with a fundamental feature of the legislation.

The Employment Appeal Tribunal held that s.146 could be rescued under the interpretative obligation, by amending the definition of ‘an appropriate time’ under s.146(2) to include ‘(c) a time within working hours when he is taking part in industrial action’. Section 146 failed to adequately protect freedom of association, giving rise to an interference with Ms Mercer’s article 11 rights, and no legislative objective had been identified that was sufficiently important so as to justify that interference. In that context, the EAT held that s.146 TULRCA could permissibly apply to industrial action, despite this interpretation applying a different definition of trade union activities to other sections of the Act.

The Secretary of State, as intervener, appealed and the Court of Appeal disagreed with the conclusions of the EAT. Whilst Strasbourg law has consistently protected lawful industrial action, the extent and duration of the protection necessary to comply with article 11 was uncertain – interpreting s.146 to prevent any detriment amounted to ‘impermissible judicial legislation’ and was a policy issue best left for Parliament. The Court of Appeal – being the first court hearing this case with the ability to make a declaration of incompatibility as per s.4 HRA – declined to do so. The court reasoned that it was not ‘appropriate to grant a declaration of incompatibility in this case where there is a lacuna in the law rather than a specific statutory provision which is incompatible the extent of the incompatibility is unclear and the legislative choices are far from being binary questions’.

The Supreme Court – Breach

The Supreme Court upheld the view that the ‘failure to provide any legislative protection at all against any sanction short of dismissal for lawful industrial action against those who take it, does put the United Kingdom in breach of its positive obligation to secure effective enjoyment of the right to participate in a lawful strike that is protected by article 11 (including as regards the private sector)’.

The ability of an employer to impose any sanction they wish, short of dismissal, for participating in lawful industrial action ‘nullifies the right to take lawful strike action. If employees can only take strike action by exposing themselves to detrimental treatment, the right dissolves’. As a result,s.146 ‘encourages and legitimises unfair and unreasonable conduct by employers’, making it difficult to see how any balance between the rights of employers and trade union members has been struck at all.

The Supreme Court – Remedy

The Supreme Court affirmed the view of the Court of Appeal and the Employment Tribunal that a convention-compliant interpretation of s.146 would amount to ‘impermissible judicial legislation’. The reference to ‘an appropriate time’ in s.146 drew a clear distinction between trade union activities that can be undertaken outside of working hours, and industrial action which is generally undertaken during working hours. It was not possible to assume Parliament would choose to protect any and all forms of detriment, which the EAT’s proposed interpretation would achieve.

The Supreme Court disagreed with the Court of Appeal’s reasoning as to the declaration of incompatibility, finding that s.146 specifically prevented the Claimant vindicating her article 11 rights, and holding that ‘the existence of policy choices in the means of giving effect to the lawful strike rights protected by article 11 is a reason in favour of making a declaration of incompatibility, not refusing one’. The Supreme Court could discern ‘no good reason’ for rejecting the remedial measure provided for by s. 4 HRA.

As such, the court declared that ‘section 146 of TULRCA is incompatible with article 11, insofar as it fails to provide any protection against sanctions, short of dismissal, intended to deter or penalise trade union members from taking part in lawful strike action organised by their trade union’.

What happens next?

It remains for Parliament to decide whether and how to remedy the incompatibility – which may be by amendment to s.146 or by other means. In the meantime, the law remains as per the statute. If Parliament does not choose to respond to the declaration of compatibility made, Ms Mercer herself can continue to pursue the matter in Strasbourg.

There is of course a question to be asked as to whether the current government has the time or any inclination to consider this question before the upcoming general election. This is, in all likelihood, a question for the next government.

More widely, this case illustrates the importance of human rights law to employment practitioners generally. It also demonstrates the limits of the interpretative obligation imposed by s.3 HRA and will be useful reading to anyone whose practice area deals with human rights issues.


Jessica Sharratt

Call: 2023

Related Practice Areas

Employment & Discrimination

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