Gas engineer's constructive dismissal claim fails; ordered to repay sick pay
A gas engineer who resigned while being investigated for working for another employer while off sick has lost his constructive unfair dismissal claim. The tribunal also ordered him to repay £2,837.10 in sick pay.
1 min read · Last updated 19 May 2026
Case details
Key facts
- The claimant was employed as a gas engineer from October 2014 until his resignation on 16 July 2021.
- The claimant lost overtime and call-out payments after an emergency rota was introduced on 25 March 2020 due to the Covid-19 pandemic.
- The claimant raised multiple grievances about health and safety, PPE, and treatment of tenants, which were investigated by the respondent.
- From December 2020, the claimant worked for British Gas via his own company while off sick and claiming company sick pay from the respondent.
- The claimant resigned on 16 July 2021, shortly after the respondent began investigating his work for British Gas.
- The tribunal found that the claimant was not constructively dismissed and that his claim of unfair dismissal failed.
Timeline
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Employment started
The claimant began working as a gas engineer for Plus Dane Housing Limited.
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Call-out pay dispute begins
A dispute arose over changes to call-out terms and conditions, which were agreed with the union.
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Emergency rota announced
The respondent announced an emergency rota due to Covid-19, suspending overtime and call-out pay.
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Emergency rota implemented
The rota took effect, and the claimant was placed on day shifts only.
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Return to work after isolation
The claimant returned to work but went home due to lack of PPE; he received a fitted mask the next day.
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Last day at work
The claimant stopped working and went off sick, never returning to work for the respondent.
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First grievance raised
The claimant raised a grievance about health and safety, bullying, and other issues.
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Started working for British Gas
The claimant began working as a contractor for British Gas via his own company while off sick.
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Grievance appeal outcome
The claimant's grievance appeal was partially upheld; he was notified of the outcome.
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Email to chairman
The claimant emailed Sir Peter Fahy with serious health and safety allegations, triggering a whistleblowing investigation.
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Collective grievance lodged
The claimant and two colleagues lodged a collective grievance, investigated by independent HR consultant Diane Johnson.
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Callow's phone call
Barry Callow called the claimant to investigate allegations of working while off sick; the claimant denied them.
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Collective grievance outcome
Diane Johnson issued her 80-page grievance report, partially upholding some complaints.
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Resignation
The claimant resigned by email to Sir Peter Fahy, citing various grievances.
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Investigation outcome
The respondent informed the claimant that British Gas confirmed he had worked since December 2020, which would have been gross misconduct.
The legal issue
The tribunal had to decide whether the employer's actions – including changes to overtime, handling of grievances, and investigating the claimant's work for another employer while off sick – amounted to a fundamental breach of contract that entitled the claimant to resign and claim constructive dismissal.
The outcome
The tribunal dismissed the claimant's unfair dismissal claim, ruling that he was not constructively dismissed. The key reason was that the employer's conduct did not breach the implied term of trust and confidence. The claimant resigned before any such breach could be established.
On the respondent's counterclaim, the tribunal ordered the claimant to repay sick pay he received while working for British Gas via his own company. The total amount was £2,837.10.
Lessons & takeaways
- If you work for another employer while on sick leave, you risk having to repay sick pay if your contract prohibits it.
- Resigning before a fundamental breach occurs can undermine a constructive dismissal claim – you need to show the employer's action was the final straw.
- Employers can investigate suspected fraud during sick leave without it necessarily being a breach of trust and confidence.
A resignation that backfired
This case shows the risks employees take when they resign in anticipation of being dismissed, rather than waiting for the employer to act. The gas engineer, who had nearly seven years' service, resigned just as his employer was investigating allegations that he had been working for British Gas while off sick and claiming company sick pay. The tribunal found that the employer's investigation was reasonable and did not breach the implied term of trust and confidence.
What the employer did right
Plus Dane Housing Limited handled the situation carefully. They investigated the claimant's grievances about health and safety and PPE, and partially upheld some of them. When they discovered he might be working elsewhere while off sick, they launched a separate investigation. The tribunal noted that the employer acted proportionately and within its rights. The claimant's decision to resign before that investigation concluded meant he could not show that the employer's conduct forced him out.
The counterclaim sting
The employer's counterclaim for repayment of sick pay was successful. The tribunal found that the claimant had been working for British Gas via his own company while signed off sick, which was a breach of the sickness absence policy. He was ordered to repay £2,837.10. This serves as a reminder that employees who work while on sick leave may have to repay any sick pay received if their contract or policy prohibits it.
Key takeaway for similar claims
Constructive dismissal claims are notoriously difficult to win. The employee must show that the employer's conduct was so serious that it fundamentally breached the contract, and that the employee resigned in response to that breach. Here, the employee jumped too soon – he resigned before the employer's investigation could be completed. If you are considering resigning and claiming constructive dismissal, it is vital to wait until the employer has committed a clear breach, and to ensure that breach is the reason you leave.
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