Dismissing Someone for Taking Industrial Action Is Now Unlimited Risk

Rounding off this week’s trio — after our pieces on the Acas Code and the tipping consultation — here’s a change that’s already been quietly in force since February, and ties directly into the trade union reforms we covered in our earlier series on the right to join a union and workplace access.

A quick explainer of the terms you’ll see

Protected industrial action — official industrial action (like a strike) that a trade union has organised properly, following the correct ballot and notice rules.
Automatically unfair dismissal — a dismissal that a tribunal must treat as unfair without needing to weigh up whether the employer acted reasonably, and without the usual minimum length of service requirement.
The old “12-week rule” — the previous protection, which only shielded an employee from dismissal for taking part in industrial action during the first 12 weeks of that action.
Detriment — being treated unfavourably (short of dismissal) — for example, being denied a promotion, having hours cut, or being excluded from opportunities.

What actually changed

From 18 February 2026, dismissing an employee for taking part in lawful, properly organised industrial action became automatically unfair — with no time limit at all.

Previously, protection from dismissal for taking part in industrial action generally only lasted for the first 12 weeks of that action. After that point, an employer could potentially dismiss someone taking part in an ongoing dispute without it automatically counting as unfair, provided they’d taken reasonable steps to try to resolve things. That 12-week cut-off is now gone entirely. If the industrial action is protected — properly balloted, correctly notified — a dismissal for taking part in it is automatically unfair, no matter how long the action has been running.

This applies to industrial action that began on or after 18 February 2026. Action that started before that date is still assessed under the old 12-week rule.

A few related changes landed alongside this on the same date, as part of a wider loosening of industrial action rules:

The 40% support threshold for strike ballots in important public services was removed.
Notice of industrial action dropped from 14 days to 10 days.
Industrial action mandates (how long a successful ballot remains valid for) increased from 6 months to 12 months.

What’s coming next: detriment protection in October

This dismissal change is only half the picture. From October 2026, workers taking part in industrial action also gain increased protection against detriment — meaning it becomes riskier to treat someone unfavourably (short of dismissal) because they took part in lawful industrial action, not just to dismiss them outright.

Combined, these changes mean industrial action — even from a small number of staff — now carries meaningfully more legal risk to manage than it did a year ago, for any employer, not just those with an existing recognised union.

Why this matters even if you’ve never dealt with industrial action

This connects directly to the reforms we’ve already covered. Lower thresholds for union recognition, an incoming right for unions to access your workplace even without existing members, and now unlimited dismissal protection for anyone taking part in official industrial action, together mean that a business with no history of union activity is no longer automatically insulated from this risk. If a dispute does emerge and escalates to industrial action, the room for manoeuvre available to an employer is now significantly narrower than it was even 18 months ago.

What employers should do now

Never treat “how long the action has run” as a factor in deciding whether dismissal is safe. There’s no time-limited safe harbour any more.
Get proper advice before any dismissal connected to industrial action, even indirectly — the automatic unfairness here removes the usual tribunal balancing exercise entirely.
Prepare for the October detriment changes by reviewing how managers are briefed on treating staff who’ve taken part in lawful industrial action — fairly, and without any perceived penalty.
Focus on early, genuine dispute resolution. With the legal room to manage a prolonged dispute through eventual dismissal now closed off, resolving the underlying dispute matters more than ever.
Revisit this alongside your trade union access and recognition preparations — these reforms are best understood as one connected shift in industrial relations risk, not isolated changes.

How Cheviot HR can help

Industrial relations risk has shifted meaningfully this year, and getting ahead of a dispute — through genuine early resolution — is now far more valuable than it used to be, given how limited an employer’s options are once action is underway. We can help you review your current approach to workplace disputes and prepare for the wider trade union changes landing this autumn.

Get in touch at heidi@cheviothr.co.uk or visit https://cheviothr.co.uk to talk through what this means for your business.