This case concerned a teacher who suffered from cystic fibrosis. Mr Grosset was former head of English at the Joseph Rowntree School, a secondary school operated by the City of York Council. The respondent employer was aware of his disability and made reasonable adjustments accordingly. Following the appointment of a new head teacher, who was unaware of Mr Grosset’s condition, the claimant was subjected to an increased workload and, as a result, became very stressed and struggled to cope with the pressures of both his job and his disease.

One afternoon the claimant allowed a class of 15 year old students to watch an 18-rated horror film. He did not obtain approval for this from the school nor did he obtain consent from the pupils' parents. Around the time of the screening Mr Grosset’s lung function had dropped to an “all-time low” and it was thought he might require a double lung transplant. Disciplinary charges were brought against him and he was dismissed for gross misconduct.

At the disciplinary the claimant accepted his actions were inappropriate. He expressed regret and remorse yet maintained he was suffering from stress and, as such, made an error in judgment arising in consequence of his disability.

The employment tribunal unanimously held the dismissal was an act of disability-related discrimination contrary to section 15 Equality Act 2010 (discrimination arising from a disability), as it applies in GB. The tribunal was satisfied that the error of judgment for which the claimant was dismissed arose in consequence of his disability. The tribunal accepted the respondent had legitimate aims in terms of safeguarding children and maintaining disciplinary standards, to which it attached significant weight. Notwithstanding, the tribunal held the dismissal was disproportionate, stating a formal written warning would have been sufficient.

The Court of Appeal had to consider the proper construction of section 15 (1) (a). This required the investigation of two distinct causative issues:
(i) did A treat B unfavourably because of an (identified) "something"? and
(ii) did that "something" arise in consequence of B's disability.

On appeal the respondent argued that it could not have treated the claimant unfavourably as it did not connect the conduct of the claimant to that of his disability and it was unaware of any such link.

The Court of Appeal rejected this argument, affirming the decision of the tribunal. The Court concluded the tribunal had correctly identified and considered the relevant legitimate aims of the respondent employer and was entitled to find dismissal a disproportionate sanction in the circumstances. Mr Grosset was awarded the substantial sum of £646,000 in compensation.

Sales LJ remarked: “This is the first time that this Court has had to consider its meaning of section 15(1) EqA, and accordingly this decision is another important landmark in the development of disability discrimination. It remains to hope that, with the detailed and definitive interpretation of the earlier legislation by the House of Lords and the intervention of Parliament, the law can now be viewed as more settled.”

N.B. The Equality Act 2010 does not apply in Northern Ireland. Instead, the laws promoting equality of opportunity for people with disabilities and outlawing disability discrimination are found in the Disability Discrimination Act 1995. In particular, the provisions of Section 15(1) EqA – discrimination arising from a disability – do not apply in Northern Ireland. Non-direct discrimination complaints (i.e. indirect or disability-related complaints) are hard to establish in NI, where tribunals are bound by the decision of the then House of Lords case of Lewisham London Borough Council v Malcolm [2008] UKHL 43, making the establishment of a comparator extremely difficult in this jurisdiction. 
http://www.bailii.org/ew/cases/EWCA/Civ/2018/1105.html