Constructive dismissal claims often hinge on whether a final incident – the so-called “last straw” – justifies an employee’s resignation. A recent EAT decision has reaffirmed that even relatively minor acts can form part of a cumulative breach of trust and confidence. This highlights the importance for employers and HR teams to manage issues consistently and respond to employee concerns before they escalate.

The “last straw” doctrine

Before looking at the recent EAT decision, it is worth exploring the “last straw” doctrine in detail.

Used in constructive dismissal claims, the doctrine allows an employee to resign and claim constructive dismissal following a final act or incident that culminates a series of unreasonable behaviours by an employer. The behaviour before the final act or incident could be potentially minor on its own – it is the culmination that is important.

For example, consider an employee who is undermined by their manager, denied training opportunities or promotions, and excluded from a team lunch. The employee is then criticised by their manager in a meeting. The employee resigns, citing the criticism in an email as the “last straw”. Whilst the email incident alone may not justify resignation, the cumulative mistreatment of the employee could amount to constructive dismissal.

The test is based objectively as to whether the conduct by an employer, over time, demonstrated that the employee could no longer be expected to remain bound by their contract of employment.

Marshall v McPherson Limited [2025] EAT 100

This case involved a long-serving HGV driver of a haulage company who resigned, claiming constructive dismissal. The claimant provided examples of unreasonable behaviour by his employer throughout his employment, such as complaints about his workload, an inability to take breaks, and a proposed move to a local driving role (which the claimant rejected and so was not paid). The claimant cited a performance check as the “last straw”, resulting in a breach of the implied term of trust and confidence, and an entitlement to resign and claim constructive dismissal.

The Employment Tribunal (ET) dismissed the claim. Despite accepting the past incidents raised by the claimant, it concluded that the “last straw” was not a fundamental breach which could justify the employee’s resignation.

The EAT overturned this decision, confirming that a relatively minor event could still amount to constructive dismissal so long as it forms part of previous unreasonable behaviour by the employer. The EAT found that the ET had misdirected itself with the reasoning that the “last straw” in this instance was insufficient.

The impact of the EAT’s decision

Whilst the EAT’s decision reiterates established law, it serves as a timely reminder of how seemingly minor incidents in the workplace can contribute to a cumulative breach of mutual trust and confidence.

The EAT’s decision reaffirmed the five-stage test set out in the case of Kaur v Leeds Teaching Hospitals NHS Trust [2018], which an employment tribunal should consider when determining constructive dismissal claims:

1. What was the most recent act (or omission) by the employer that caused or triggered the resignation?
2. Has the employee affirmed the employment contract?
3. If not, was the act (or omission) a repudiatory breach itself?
4. If not, was it part of a course of conduct which cumulatively amounted to a repudiatory breach of the implied term of trust and confidence?
5. Did the employee resign in response to that breach?

The ET’s failure to properly consider grounds four and five was one of the reasons the EAT gave when overturning the decision.

Key points for employers

The decision highlights that a build-up of issues, even seemingly minor ones, can result in a breach of mutual trust and confidence and a successful constructive dismissal claim. Employers should:

1. Take employee complaints or concerns seriously and respond to them promptly and transparently. Failure to do so could result in a pattern of unresolved issues.
2. Ensure the accumulation of unresolved issues and employee concerns is avoided, and follow up on historic complaints to prevent them from resurfacing.
3. Ensure those managing grievances or performance-related issues are trained and follow the correct reporting procedures.
4. Review policies and procedures regularly to prevent misunderstandings or complaints.
5. Document everything: maintain records of complaints, responses, and decisions to demonstrate fair and consistent handling.

The case also highlights how intent may not always protect against a breach. The provision of a colleague to monitor performance or help another employee may, in certain circumstances, undermine trust and confidence, no matter how well intentioned – and could, if combined with other issues, result in a breach of trust.

How TWM can help

At TWM Solicitors, we understand the complexities and risks employers face when managing workplace disputes. The EAT decision highlights how even minor missteps can escalate into constructive dismissal claims under the “last straw” doctrine.

Our Employment Law team offers proactive, practical advice to help mitigate these risks – we can review grievance procedures, provide training courses for HR professionals and managers, and advise on risk management strategies. We help employers navigate sensitive situations with confidence, ensuring compliance and preserving trust within the workforce.