[Once] an employer knows, or reasonably ought to know, that one of its employee’s is a disabled person within the meaning of the Equality Act 2010, the employer is under a “duty” to make “reasonable adjustments” to ensure that the employee is not placed at a [substantial disadvantage] in comparison to those people (employees’) who are not disabled pursuant to s.20(3); s.21 and s.39(5) of the Equality Act 2010. The key here is to ask yourself whether your employer is aware that you have a disability? If not, then make sure you inform the employer in your grievance letter that you have a disability/impairment. In this regard, I refer you to the Statutory Code of Practice on Employment 2010; Chapter 5 Paragraph 5.15:
“It is not enough for the employer to show that they did not know that the disabled person had the disability. They must also show that they could not reasonably have been expected to know about it. Employers should consider whether a worker has a disability even where one has not been formally disclosed, as, for example, not all workers who meet the definition of disability may think of themselves as a ‘disabled person’.”
For a list of legally recognised disabilities, click here.
It is incumbent upon your employer to undertake a proper assessment of your condition/s in consultation with you, as evidence by the casse precedent of Tarbuck v Sainsburys Supermarkets Ltd  IRLR 664 paragraphs 69 & 72:
 “There can be no doubt that any employer would be wise to consult with a disabled employee in order to be better informed and fully acquainted of all the factors which may be relevant to a determination of what adjustment should reasonably be made in the circumstances. If the employer fails to do that, then he is placing himself seriously at risk of not taking appropriate steps because of his own ignorance. He cannot then pray that ignorance in aid if it is alleged that he ought to have taken certain steps and he has failed to do so. The issue for the Tribunal will then be whether it was reasonable to take that step or not.”
 “Accordingly whilst, as we have emphasised, it will always be good practice for the employer to consult and it will potentially jeopardise the employer’s legal position if he does not do so- because the employer cannot use the lack of knowledge that would have resulted from consultation as a shield to defend a complaint that he has not made reasonable adjustments- there is no separate and distinct duty of this kind.”
Reasonable and Practicable Steps
The employer shall take [reasonable and practicable steps] to ensure its employees’ [health and safety] whilst at work pursuant to s.1(1)(a) of the HSAWA 1974.
Section 2(1) of the Health and Safety At Work Act 1974: “It shall be the duty of every employer to ensure, so far as is ‘reasonably practicable’ the health, safety and welfare at work of all his employees.”
Let’s break down the above sentence, and see what it is actually stating.
The employers “relevant duty” is to “ensure” as is “reasonably practicable” the “health”, “safety” and “welfare” of his employees’.
A contravention of the HSWA 1974, may potentially amount to a breach of the contract of employment.