No, the disabled need not invoke the Equality Act 2010 (henceforth "EqA"). See EqA, section 15(2).
(2) Subsection (1) does not apply if A shows that A did not know, and could not reasonably have been expected to know, that B had the disability.
See Aileen McColgan KC, Discrimination Law
Text, Cases and Materials 2023 3rd edn. Page 508.
A finding of disability discrimination may require that the discriminator had actual or
constructive/imputed knowledge of the disability (that is, that the discriminator knew or
should in all the circumstances have known that the claimant was disabled).35 The CA ruled in
Gallop v Newport CC  EWCA Civ 1358,  IRLR 211 that the required knowledge
is not of the diagnosis or of the fact that the claimant falls within the statutory definition
of disability. Rather, it relates to the facts, namely (1) that the claimant has a physical or
mental impairment which (2) has a substantial and long-term adverse effect on (3) his or her
ability to carry out normal day-to-day activities. The employer in the Gallop case had relied
on (incorrect and unreasoned) advice from its Occupational Health advisers that the claimant
did not meet the statutory definition of disability. The CA ruled that this advice did
not alter the fact that the employer had constructive knowledge of the claimant’s disability.
The outcome might well have been different had the employer been incorrectly advised as
to the facts (that is, whether the claimant had a physical or mental impairment, whether
it impacted on the claimant’s ability to carry out normal day-to-day activities and, if so,
whether this impact was substantial and long-term). It might also have been different had
the OH advice been reasoned.
35 Gallop v Newport CC (direct discrimination); s15(2) EqA (s15 discrimination, though the burden of proof
is on the respondent) and Schedule 8 para 20 EqA (failure to make reasonable adjustments, which relates to
Part 5 only).
Although s15(2) EqA requires actual or constructive knowledge of the disability on the
part of the discriminator, there is no requirement that the discriminator know that the
‘something’ is connected with that disability.42 Thus, for example, in City of York Council
v Grosset (referred to by Simler P in the extract immediately above), the CA ruled that a
tribunal was entitled to find that a teacher who had been dismissed for showing children an
unsuitable film had been discriminated against contrary to s15 where the error in judgment
was the result of stress which in turn arose in consequence of the efforts he had to make to
manage his cystic fibrosis. It did not matter whether the employer was aware that the claimant’s
stress was related to his cystic fibrosis. As Arden LJ put it at §67, ‘s 15(2) is inconsistent
with any suggestion that lack of knowledge of the consequences is a defence. I can also
well understand that Parliament could have taken the view that if lack of knowledge of
the consequences were a defence, that could well in practice undermine the wide protection
already given by s 15(1) EqA’.
42 City of York Council v Grosset  EWCA Civ 1105,  ICR 1492.