← Back to case studies
Case law
Mobbs v Weetabix Ltd

A manager’s abusive language and a botched grievance process can add up to constructive dismissal, even without one knockout incident.

The ruling

“Constructive unfair dismissal upheld; compensation to be assessed at a separate remedy hearing.”

A slow or superficial grievance investigation can itself help prove constructive dismissal, on top of whatever conduct you originally complained about.

  • Keep a written record of how long your grievance investigation takes and whether the witnesses you named were actually interviewed.
  • If the outcome letter contradicts evidence the investigation itself gathered, that mismatch is worth raising, in the grievance appeal and later if needed.
  • You do not need one single serious incident. A pattern of conduct, combined with how badly your employer handles your complaint about it, can together amount to a breach of trust and confidence.
Read the full case

The situation

After more than 25 years with the company, an employee raised a formal grievance about his manager's language and behaviour towards him and colleagues. That manager had repeatedly sworn at and about staff, called a colleague "useless" and "a fucking idiot," and dismissed another as likely to "start crying." The employee raised a grievance. It took the investigator 34 days to interview the witnesses he had named. The outcome letter rejected his complaints anyway, even though witnesses had described the manager's behaviour as capable of being humiliating. His appeal fared no better: the appeal officer took no notes and had not even read the company's own dignity-at-work policy before hearing it. Signed off sick, the employee resigned.

What the tribunal found

The tribunal held this was a constructive unfair dismissal. The manager's language was, on its own, serious enough to damage trust and confidence. But the way the grievance was handled made things worse, not better. A 34-day delay in speaking to named witnesses fell outside what any reasonable employer would do, and the tribunal did not accept the investigator's explanation for it. The outcome itself was found "flawed," reaching conclusions that were "an overstatement not borne out" by the evidence the investigation had actually gathered. The appeal was no more careful. Taken together, the abusive conduct and the mishandled grievance breached the implied term of trust and confidence that underpins every employment contract, entitling the employee to resign and treat himself as dismissed.

That implied duty runs through our case study on Malik v Bank of Credit and Commerce International, where the same trust and confidence principle first took shape.

Full citation

Mobbs v Weetabix Ltd. Case 3307596/2020. Employment Tribunal (Huntingdon). 9 January 2023.

Last reviewed 20 July 2026