The Claimant, who holds the belief that biological sex is real, important, immutable and not to be conflated with gender identity, made comments on Twitter that some of her colleagues found offensive. When her consultancy contract was not renewed, she brought proceedings before the ET on the basis that, amongst other claims, she had been discriminated against because of her belief. The ET concluded that the Claimant's belief – having regard to its "absolutist" nature, whereby she would "refer to a person by the sex she considers appropriate even if it violates their dignity and/or creates an intimidating, hostile, degrading or offensive environment" – was one that was "not worthy of respect in a democratic society" in accordance with the fifth criterion in Grainger plc and others v Nicholson [2010] IRLR 4, and so it found that the Claimant's belief was not a "philosophical belief" within the meaning of section 10 of the Equality Act 2010 ("EqA"). The Claimant appealed on the basis that the ET erred in law in its approach to the fifth criterion in Grainger.

The EAT held that the ET had erred in law; in relation to the preliminary issue of whether the Claimant's belief fell within section 10 of the EqA, the EAT substituted a finding that it did. Accordingly, the matter would be remitted to a fresh ET to determine whether the treatment of the Claimant was because of, or related to, that belief.