Legal Update
Disability, Delusions and Definitions.
4 November 2020

Disability, Delusions and Definitions.

Author: Gareth Price


Disability is defined in s.6 of the Equality Act 2010 (“EqA 2010”) as

“A person (P) has a disability if—

P has a physical or mental impairment, and

the impairment has a substantial and long-term adverse effect on P's ability to carry out normal day-to-day activities.”

Employees that suffer from a disability so defined are protected against various forms of discrimination because of that status. Employers facing claims of such discrimination must assess whether a Tribunal will find that the employee was in fact, during the relevant period, disabled and, if so, whether it knew or reasonably ought to have known of that fact. It is common for employers to concede the fact of disability.

A recent EAT decision has explored the concepts of ‘substantial adverse effect’, ‘long-term’ and knowledge and, in dosing so, provides employers with helpful guidance when assessing whether to challenge or make that concession.  

Sullivan v Bury Street Capital Limited

The Claimant was employed as a sales executive from 2008 until September 2017. In 2013 he became convinced he was being monitored by a Russian gang, including by way of electronic surveillance. This caused him to not put appointments in his electronic calendar, in an effort to hamper their efforts.

The Claimant’s manager became aware of these beliefs in 2013. In September 2013 a business trip to New York took place during which the Claimant appeared well and capable of performing in his role.

The Claimant then consulted with healthcare professionals from 2014 regarding these beliefs. The belief persisted. The Claimant was nonetheless able to maintain his employment throughout this time.

From 2014 to 2017 regular performance reviews repeatedly highlighted timekeeping and attitude as issues of concern which lead to the Respondent contemplating dismissal.

After the final review in around July 2017, the Claimant went off sick for four weeks. The Respondent terminated the Claimant’s employment shortly thereafter. The reasons given included timekeeping. 

Claims and expert evidence

The Claimant brought several claims including disability discrimination (s.15, s.19 and s.20/21 EqA 2010).

The Claimant contended he was disabled by reason of paranoia and that the relevant period of that disability was August 2013 until September 2017.

There was a jointly instructed expert who had stated in his report that there was a substantial adverse effect on the Claimant during the relevant period. In cross-examination, the expert accepted he could not be sure about the Claimant’s condition.    

ET findings

The Tribunal found that the Claimant was not disabled for the purpose of the EqA 2010 as any substantial adverse effect (“SAE” or the “SAE issue”) on his ability to carry out normal day to day activities did not extend beyond September 2013 (the date of the New York business trip).

It also found that the SAE reoccurred in around July 2017, but was not likely to continue for at least 12 months.

In the alternative the Tribunal found that the Respondent did not, nor could be reasonably expected to have known, about the Claimant’s disability during the relevant period. 

Appeal and EAT decision

The Claimant appealed these findings.

The two overarching bases of appeal were that:

-        It was not open to the Tribunal to not find that there was SAE on the Claimant’s ability to carry out day to day activities; and

-        The ET’s findings as to knowledge were in error. 

The SAE issue

The EAT set out a summary of the relevant legal principles applicable to determining the question of disability. In particular, it noted that:

-        Likely” means something that could well happen; SCA Packaging v Boyle [2009] ICR 1056; and

-        Likelihood of reoccurrence is to be assessed as at the time of the alleged contravention; McDougall v Richmond Adult Community College [2008] ICR 431

First, it found the ET had correctly drawn a distinction between continuation of the symptoms (here the paranoid beliefs) and any SAE caused by those symptoms.

Second, it found the ET had adequately explained its reasons for rejecting the Claimant’s evidence, including the evidence of the expert. In particular, it noted that the expert’s concession in oral evidence (albeit not a significant departure from the written opinion alone) was supported or corroborated by other lay evidence as to the Claimant’s day to day condition.

Third, the EAT referred to the Presidential Guidance, concerning disability, and that it remains for the Tribunal to assess whether any symptoms (such as delusional beliefs) in fact have a SAE. 


First, the EAT rejected the argument that because the SAE did reoccur (in 2017), that necessarily meant that the ET had to find that the SAE continued from 2013 onwards – applying McDougall.

Second, an argument that the low threshold of “could well happen” is met simply because it did in fact reoccur was also rejected – although the EAT noted that reoccurrence episodically might “strongly suggest” meeting that threshold.

Third, evidence that an employee’s condition is expected to continue for many months (suggesting it could well happen to persist for 12 months or more) is not evidence that that condition will have SAE on the Claimant for that period. 


The EAT set out what it stated was the proper approach to this issue, from the decision of HHJ Eady QC in A Ltd. v Z [2020] ICR 199.

The EAT rejected this ground of appeal also.

In particular it held that mere knowledge of some sort/degree of mental impairment was not sufficient. It must also be shown that the Respondent knew (actually or constructively) that the impairment had a SAE on the Claimant and that that was long-term.

On the facts, it was open to the ET to find that the Respondent did not have such knowledge. 


It can be very difficult for a Respondent to challenge an allegation of disability.

Very often the point is conceded.

Sometimes that is because the Respondent properly accepts the Claimant exhibited (or has subsequently demonstrated) the effects of their impairment and that it was aware (or ought to have been aware) of the same during the relevant period. Conscientious and fair-minded employers will not pose improper hurdles on disabled employees bringing such claims.

Equally, sometimes that concession is made because, after receiving further information (perhaps in the form of an impact statement during the course of proceedings) the position is taken that:

-        The statements cannot sensibly be challenged;

-        It has no positive evidence to the contrary; and

-        If those findings were accepted, then it would plainly meet the EqA 2010 test.

In those circumstances, the Respondent is usually left with only arguing knowledge (actual or constructive).

However, this decision highlights that, where proper, the following issues can be put in issue.

-        The EqA 2010 has many strands, each of which must be satisfied. That burden is on the Claimant;

-        Reoccurrence/episodical effects are often relied on by Claimants, but Tribunals must not err by looking back with the knowledge of later reoccurrence;

-        Triggering events of an episode might (depending on the event) lead to the conclusion that an impairment is not ‘long-term’;

-        Whilst it may be hard to challenge the state of condition/impairment, a more fruitful area of challenge may be whether that condition/impairment in fact has an SAE on the Claimant’s day to day activities;

-        Whilst SAE is not confined to looking at the cause of any detriment at work (such as when applying the s.15 EqA 2010 test), focusing challenges on those aspects of any condition/impairment may be worthwhile (and more feasible given the availability of witnesses to the Claimant’s work and presentation at work);

-        A Ltd v Z is a valuable authority for Respondents who have a genuine and reasonable position to take as to lack of knowledge.

Indeed, the two decisions of A Ltd v Z and Sullivan provide helpful guidance to an employer that considers either the fact of the disability or its knowledge of the same are capable of challenge.


View Gareth Price's profile on this link.