Warburton v Chief Constable of Northamptonshire Police (EAT)

In brief

The EAT allowed an appeal against an Employment Tribunal's finding of no victimisation. The EAT held the tribunal had applied the wrong test for (a) detriment and (b) causation in a victimisation claim under EA 2010 s.27. On detriment: following Shamoon, the question is whether a reasonable worker might consider themselves to have been put to disadvantage in the circumstances; the threshold is not high and is not a wholly objective test. On causation: the question is whether the protected act had a 'significant influence' on the outcome. The case was remitted for rehearing. The protected act was the claimant's pending ET proceedings alleging disability discrimination against another police force; Northamptonshire Police had suspended his vetting process 'until resolved'.

Key provisions

• shamoon-detriment-test — Shamoon detriment test — broader than it appears: Following Shamoon: detriment is established where a reasonable worker might consider themselves to have been put to disadvantage in the circumstances. The threshold is not high. The test is NOT wholly objective — it incorporates the worker's reasonable perspective on disadvantage.
• significant-influence-causation — 'Significant influence' causation test in s.27 victimisation: The question is whether the protected act had a 'significant influence' on the outcome — not whether it was the sole or even dominant cause. The protected act need not be the only reason; it must be a significant influence.

When relevant

Cite when: (a) respondent argues no detriment was suffered in a victimisation claim; (b) respondent argues the protected act was not the cause (sole or dominant) of adverse treatment; (c) modern s.27 victimisation analysis is needed — WARBURTON is the leading EAT authority on detriment + causation; (d) TNB cases where adverse action followed a trans-related grievance / claim; (e) pair with JESSEMEY-CA-2014 for post-employment victimisation context, KHAN-UKHL-2001 for the foundational causation framework.