The resignation letter almost never comes out of nowhere.
By the time a resignation letter lands on your desk, the employee sending it has usually spent months, sometimes years, quietly building the case in their own head. Every unanswered grievance. Every promise made in a review and not kept. Every moment they raised something and nothing changed.
Nobody sees the case being built. That is what makes it so easy to miss.
What constructive dismissal actually is
Constructive dismissal happens when an employer breaches the employment contract so seriously that the employee feels they have no real choice but to resign. Tribunals also recognise the "last straw" doctrine, where a series of smaller issues, none huge on its own, builds until one final act pushes someone out the door.
The important detail most employers miss is that the smaller issues can be entirely mundane. Missed promises. Unanswered emails. A grievance sitting in a manager's inbox for four months. These are the building blocks of a claim, and they usually feel like nothing at the time.
Why 2026 is different
Constructive dismissal claims are rising in the UK, and it is not because employees have become more litigious. Three things are shifting under employers' feet at once.
Employees are far better informed than they were five years ago. Social media has quietly done a lot of HR's education work for it. People know the difference between a poor manager and an unlawful one, and they know what a paper trail looks like.
Hybrid working has made it much harder for managers to spot when someone is quietly disengaging. The daily signals that used to be obvious in an office (someone going quiet, sitting apart, arriving late, leaving early) simply are not visible when everyone is on Teams. Disengagement now happens in the background, and often for months before anyone notices.
And the tighter job market means fewer employees resign on impulse. They tend to build a paper trail first, then leave with the case already documented.
The everyday breaches that build a case
Most constructive dismissal claims are built from things that felt manageable at the time. Small enough that nobody thought to flag them. Ordinary enough that they blended into a busy month.
A grievance quietly sitting unanswered for weeks
A change to someone's role or hours that nobody properly consulted them on
Ongoing behaviour from a colleague or manager that keeps getting brushed off
A promise made in a performance conversation and never followed through
A reasonable request for support or adjustment that gets a "leave it with me" and never comes back
Any one of these, left long enough, becomes the specific line an employee points to in a tribunal bundle.
Where employers usually get caught out
The interesting thing about constructive dismissal is that the big, obvious moments are rarely the problem. Restructures, disciplinary action, and redundancies get scrutinised carefully because they feel legally weighty.
What actually catches employers out is the quiet neglect. The grievance that sat for three months. The manager who said "leave it with me" six weeks ago and never came back. The small changes to someone's role that piled up without anyone ever having the conversation.
None of these feel like a crisis at the time. Right up until someone resigns and starts listing dates, times, and unanswered emails.
What to do about it, quietly
Respond to grievances properly, and within a reasonable timeframe, every single time. No exceptions.
Train managers to spot disengagement early, before it hardens into resignation.
Keep a written record of anything agreed in reviews and one-to-ones, so nothing quietly disappears.
Involve the employee in any change to their role, pay, or hours, in a proper conversation before anything is decided.
Most of this costs nothing but attention. That is precisely why so many businesses skip it.
One last thing
Constructive dismissal claims are almost always built from a dozen small decisions that nobody thought were worth fixing at the time. Which means the actual prevention work is quiet, ordinary, and slightly boring. Answer the grievance. Keep the promise. Have the conversation. Follow up.
If a grievance in your business has been sitting quietly for a while, please have a look at it this week because the person who sent it is almost certainly noticing.
You know where I am. Kettle on. 🫶
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