This comes after the government attempted to increase restrictions on strike action, which included passing legislation that would require minimum service levels for striking workers in July 2023.
The Supreme Court ruled that previous interpretation of the UK law is at odds with the ECHR.
While UK law bans employers from dismissing employees for taking part in protected industrial action, the legislation was previously interpreted as not including a ban subjecting employees to a detriment short of dismissal.
This decision ruled that detriment against striking workers would no longer be allowed as it was incompatible with the ECHR.
Amanda Lennon, employment partner at Spencer West LLP, told HR magazine that this decision will increase the protections for striking workers in the UK.
She said: “[This decision] further ties the hands of employers in taking action against employees who plan and take strike action, which can disrupt the employer's operations.
“Strike action is a right enshrined in UK law but it is subject to some very strict parameters that employees and their unions need to ensure they meet.”
The ruling came as part of an appeal in the case of Fiona Mercer versus Alternative Futures Group (AFG).
In 2020, Mercer brought a tribunal claim against her employer, the charity AFG, for victimisation.
Mercer took part in strikes organised by the union UNISON against AFG, who had planned pay cuts for care staff that worked sleep-in shifts.
Read more: High Court blocks move to alter strike laws: what it means for HR
Following the strike action, AFG suspended Mercer and barred her from going to work or contacting colleagues.
The tribunal noted that, although she was paid during the time she was suspended, she was prevented from accessing pay for the overtime that she would have otherwise worked.
The 2020 tribunal found in Mercer’s favour, and said that the law should protect her from being victimised for going on strike.
Subsequently the then business secretary, Kwasi Kwarteng, appealed the case to the Court of Appeal, which reversed the decision. UNISON then escalated the case to the Supreme Court, which made its judgement this week after a hearing in December 2023.
Chris Syder, employment law partner at Penningtons Manches Cooper, explained that employers will need to rethink their strike action policies in light of this decision.
Read more: How strike laws and restrictions differ across Europe
Speaking to HR magazine, he said: “In the meantime, employers are going to have to rethink their strategies to disincentivise employees from participating in lawful strike action.
“This decision will be publicised far and wide within the UK trade union movement, meaning that staff are more likely to complain if employers subject them to say, a disciplinary penalty for joining a lawful strike.”
He added that the decision would encourage employers to resolve disputes around strike action.
Syder continued: “[The Supreme Court's decision] is likely to focus employers’ minds on the early resolution of disputes, and [may encourage them to] increase efforts to improve current employee relations.
“This is, after all, a significant victory for the trade unions and will be utilised to call out poor employer negotiation strategies to pressurise staff not to support a lawful strike.”
Lennon explained that this decision does not change the current law but means that parliament is likely to reconsider the laws surrounding the protection of striking workers, in line with the ECHR.
She said: “No changes have been made to the law yet – the judgement means that the UK parliament now has to reconsider the relevant legislation and amend it to make it compatible with the ECHR.
“This takes time as an amendment bill will have to pass through the various stages of parliament.”