Whistleblowing Law Round-Up
As we dive into 2026, we take a moment to reflect on significant judgments in the last year in whistleblowing case law:
The EAT in Argence-Lafon v Ark Syndicate Management Limited established that while whistleblowing disclosures can be protected where there is a reasonable belief in wrongdoing and that the disclosures are in the public interest, later repeated disclosures may lose their protection if ongoing investigations make that belief no longer reasonable.
The case also confirms that causation is central for detriment and automatic unfair dismissal. The detriments (including the detriment of dismissal) must be shown to be on the grounds of making the protected disclosures to be successful.
You can read the judgment here.
Whilst Oni and others v London Borough of Waltham Forest and others established that denying foster carers the right to whistleblowing and discrimination protection was an unjustified interference with their human rights under Articles 10 and 8, when read in conjunction with Article 14, the Court of Appeal in Sullivan v Isle of Wight Council held that job applicants (other than those applying for jobs in the NHS) are unable to rely on whistleblowing protections. The Court considered that external applicants could qualify for ‘other’ status, but distinguished them from those ‘in work’ such as workers of NHS job applicants.
You can read the judgment here.
The case of Day v Lewisham and Greenwich NHS Trust held that former employees can rely on whistleblowing protections where the detrimental treatment is closely connected to their employment and the protected disclosures.
The case involved Dr Day, who was employed between 2013 – 2014. He brought a whistleblowing claim in 2014 claiming he suffered detrimental treatment for reporting patient safety concerns, which settled during the hearing.
In 2019 Dr Day brought a further claim, alleging that a series of public statements made by the NHS Trust after the settlement constituted a detriment and were caused by the protected disclosures he had made. As part of this case, the ET held that whistleblowing protection was reserved for employees.
However, the EAT confirmed that whistleblower protection can apply to post-employment detriments, provided they are closely connected to the employment relationship. They ruled that the Trust’s statements, which were made in the context of the earlier litigation and disclosures being made during the employment, met this threshold. That said, it was still concluded that these statements were not materially influenced by the disclosures, rather by a desire to protect the Trust’s reputation.
You can read the judgment here.
Then in November the Court of Appeal decision in the linked cases of Wicked Vision / Treadwell gave a significant judgment regarding the relationship of whistleblowing detriment claims under Part V of the Employment Rights Act 1996 (ERA) and automatic unfair dismissal claims under Part X.
The Court of Appeal looked at the case of Osipov, where it was held that an employee can sue co-workers under section 47B(1A) for the detriment of dismissal (being party to the decision to dismiss) and rely on the employer’s vicarious liability under section 47B(1B). Osipov described section 47B(2) as excluding only a claim against the employer for its “own act of dismissal”, not claims against co-workers or the employer vicariously.
In Wicked Vision, the Court of Appeal held it was bound by Osipov to permit employees to pursue section 47B detriment claims for the “detriment of dismissal” against co-workers and the employer vicariously, alongside an automatic unfair dismissal claim under section 103A.
It should be noted however that the Court stated that they respectfully disagreed with the interpretation of the legislation in Osipov, and if they had been free to depart from that decision they would have done so.
This means that claimants in whistleblowing dismissal cases will still want to plead both automatic unfair dismissal under s103A (Part X) and detriment under section 47B (1A) against co-workers for the “detriment of dismissal”, with the employer sued vicariously under section 47B(1B). It is not necessary to have joined the co-worker to claim vicarious liability against the employer, but this may be strategically advantageous.
You can read the judgment here.
Finally, and most recently, there has been a landmark win for whistleblowing protection at the Court of Appeal, in the case of Rogerson v Erhard-Jensen Ontological Initiative Ltd. In this case the Court of Appeal held with a unanimous decision that Judicial Proceedings Immunity (JPI) cannot apply to the commencement of proceedings aimed at stifling protected disclosures or penalising someone for making them.
Please click here for a full write up on this case.
CSJ Legal
CSJ Legal has a wealth of experience in the area of whistleblowing law. If a whistleblowing situation has affected you or your business and you wish to seek advice, please contact CSJ Legal here.