Terence Herbert, CEO of Wiltshire Council, sent an email to staff who were members of the GMB union the day before they were due to be balloted for the strike action in November 2022.
The Wiltshire Council wardens planned to strike over proposed changes to their contract that would remove extra pay for working unsociable hours, which they said could cost staff up to 20% of their salaries.
A GMB representative told the Bristol tribunal in February 2024 that the email was threatening in tone and appeared to suggest a pay offer could be taken off the table if workers went ahead with the strike.
"Should we be unable to reach agreement, we will need to review whether this offer remains on the table," the email stated.
The email also claimed that the council wished to resolve the problem and asked staff to "please consider carefully whether further strike action will support this approach".
At the time, Unison and Unite the Union, two other unions that represented council workers, had already reached an agreement over out-of-hours pay.
Read more: High Court blocks move to alter strike laws: what it means for HR
In an April 2024 statement Andy Newman, GMB branch secretary, said: “The email was unlawful and as far as GMB is concerned it was a bully-boy ploy to intimidate staff from voting 'yes' to industrial action.
"It is time for Wiltshire Council to put this long-running industrial dispute to bed, and withdraw the threat of the pay cut for staff working unsocial hours."
Wiltshire Council told the tribunal that the purpose of the email was to set the record straight. Herbert maintained that the email was his attempt to correct “misleading” statements from GMB.
In March 2024, the tribunal found that the staff who received the email “were subjected to a detriment on grounds related to union activities”.
The council is now appealing the tribunal decision.
Kash Dosanjh, associate at Wright Hassall, told HR magazine that the case demonstrated employees were protected by law leading up to industrial action.
He commented: “The case shows that in the midst of an official strike, and subject to the trade union following all legal rules before declaring a strike, employees are protected by industrial action law.
“This case outlines that a mere email sent by the CEO can result in legal action taken against an employer.”
Charlie Barnes, director and head of employment legal services at RSM UK, explained that employers should be careful to not discourage workers from taking part in strikes to avoid legal action.
Speaking to HR magazine, he said: “Industrial action can be disruptive and damaging to employers, so it’s understandable they may explore options to avoid or prevent their workers from taking part.
“However, they must tread carefully when doing so to mitigate the risk of exposing themselves to legal action. Inducing workers not to take part or treating them to their detriment for doing so is unlawful.”
Read more: Punishing strikers violates human rights, Supreme Court rules
Dosanjh added that employers should be careful in their communications when leading up to industrial action to avoid imposing detriment on employees.
He continued: “If employees are contemplating strike action, they have additional rights, subject to them behaving legally, therefore employers need to be mindful about any correspondence or action leading up to a potential strike.
“During this period, employers need to be aware that they should not subject their employees to a detriment due to the strike action. In addition, employees who have participated in strike action will have unfair dismissal rights if the employer dismisses an employee participating for striking."
On 16 April, the Supreme Court ruled punishing employees who had taken part in strike action was a violation of human rights. Previously UK legislation was interpreted to allow employers to subject employees to detriment short of dismissal.
The UK government will have to amend current strikes legislation in line with this decision.
