This is the case of the former head of English who was suffering from stress exacerbated by cystic fibrosis.

He was dismissed after screening an 18-rated horror movie to 15 and 16-year-olds despite explaining in mitigation that his judgement was affected by his stress.

Grosset disclosed his condition when he started the role in 2011 and the head teacher at the time made reasonable adjustments.

In 2013, due to internal changes, there was a marked increase in his workload.

At one point, Grosset wrote to the head to complain of “unreasonable deadlines, workload and pressure”.

At a meeting on 15 October 2013, the head teacher agreed that Grosset should be referred to occupational health, but did not accept his points on workload and pressure.

Around this time, Grosset’s lung function dropped to an “all-time low” and he faced concerns that he might require a double lung transplant.

Across two separate lessons on 8 November and 11 November 2013, the teacher showed his GCSE students the horror film Halloween, intending for the film to be “a vehicle for discussion in the class about construction of narrative”.

He did not inform the school in advance and he did not obtain consent from the children’s parents.

On 27 November 2013, Grosset was signed off work because of stress.

His headteacher covered some of his lessons and, in doing so, learned about the film screening.

Grosset was suspended from his role while an investigation took place.

During the course of this, he was interviewed.

During this process he acknowledged that the film choice had been “inappropriate and regrettable” but in mitigation explained that this had been affected by stress “contributed to by his cystic fibrosis.

After a disciplinary hearing in 2014, Grosset was summarily dismissed.

He appealed the decision but was unsuccessful.

Grosset took his case to an employment tribunal, which found that he had been discriminated against because of his disability for the purposes of section 15 of the Equality Act 2010.

The Court of Appeal upheld that decision on Tuesday and it has been reported that he has received a payout of £646,000.

The case underlines the importance of employers obtaining medical advice that assesses the possible impact of any medical condition or disability before considering dismissal.