Secretary of State For the Department for Work and Pensions V Alam  UKEAT (9 Nov 2009)
The Tribunal was required to consider whether the provisions of section 4A(3) and 4A(3)(b) of the DDA applied so as to show that the Respondent was not under any duty to make reasonable adjustments.
"(3) Nothing in this section imposes any duty on an employer in relation to a disabled person if the employer does not know, and could not be reasonably expected to know.–
(b) in any case, that that person has a disability and is likely to be affected in the way mentioned in subsection (1)."
as a matter of statutory interpretation and giving the language of those provisions their ordinary meaning, that to ascertain whether the exemption from the obligation to make reasonable adjustments provided for by section 4A(3) and 4A(3)(b) applies, two questions arise. They are:
1. Did the employer know both that the employee was disabled and that his disability was liable to affect him in the manner set out in section 4A(1)? If the answer to that question is: "no" then there is a second question, namely,
2. Ought the employer to have known both that the employee was disabled and that his disability was liable to affect him in the manner set out in section 4A(1)?
If the answer to that second question is: "no", then the section does not impose any duty to make reasonable adjustments. Thus, the employer will qualify for the exemption from any duty to make reasonable adjustments if both those questions are answered in the negative. That interpretation takes proper account not only of the use, twice, of the word "and" but also of the comma after "know" in the second line of section 4A(3).
Section 4A(1) of the DDA provides:
"(1) Where –
(a) a provision, criterion or practice applied by or on behalf of an employer, or
(b) any physical feature of premises occupied by the employer,
places the disabled person concerned at a substantial disadvantage in comparison with persons who are not disabled , it is the duty of the employer to take such steps as it is reasonable , in all the circumstances of the case, for him to have to take in order to prevent the provision , criterion or practice , or feature , having that effect."