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Disability: “Physical or mental impairment”

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Last updated 11th April, 2023.

Stammering is a physical or mental impairment. It is less clear which it is (physical or mental), but this does not matter. One case suggests the speech aspects are a “physical” impairment.


Stammering is clearly a “physical or mental impairment”.

Is it “physical” or “mental”? This does not matter. However, stammering may well be “physical”, at least as regards its effect on speech as opposed to more psychological components such as avoiding situations.

(Bear in mind that to be a disability within the Equality Act 2010, the physical or mental impairment must also have a substantial and long-term adverse effect on one’s ability to carry out normal day-to-day activities.)

“Physical or mental” impairment

Stammering is clearly an impairment.

Also stammering is a “physical or mental” impairment. “Physical or mental” is not interpreted narrowly to exclude some types of impairment. The legislative history (below) endorses this wide approach.

B v Servisair (UK) Ltd 2004, Employment Tribunal
A tribunal rejected the employer’s argument that a speech impediment was not a “physical or mental impairment”.

“Physical” or “mental”?

Which is stammering, “physical” or “mental”?

The main point is that it does not matter – see below Some guidance and cases. It is not necessary to decide whether it is “physical” or “mental”.

Cases indicate that one looks at the “impairment” rather than its cause (eg below Walker v Sita). This appears to involve looking at whether the effects of the impairment are physical or mental. Stammering seems to be “physical” as regards its effect in producing stammered speech. As regards the various ways people try to avoid stammering (see Hiding the stammer), whether it be effects on their speech or eg avoiding particular situations, perhaps that is a mix of mental and physical.

The causes of stammering should not be relevant under the Equality Act. However research indicates that developmental stammering (stammering which starts in childhood) is neurological. Structural and functional differences have been found in the brains of people who stammer compared with people who do not. There is also genetic evidence. On both brain and genetic research, see The new neuroscience of stuttering (knowablemagazine.org), February 2020 and The science of stammering (archive of stammering.org), July 2016.

B v Servisair (UK) Ltd 2004, Employment Tribunal
A tribunal considered a “speech impediment” to be a physical impairment.
This case considered speech aspects of the stammer, but not psychological aspects which may be seen as at least partly “mental”.

I have a separate page on stammering starting in adulthood which considers “physical or mental impairment” in relation to that.

Some guidance and cases

Walker v Sita Information (bailii.org), Employment Appeal Tribunal (EAT), 2013
The claimant suffered from a wide range of symptoms which could not be attributed to a recognisable pathological or mental cause. They were regarded as functional overlay, accentuated by his being obese. The employment tribunal held that he did not have a physical or mental impairment because no physical or organic cause for the symptoms could be identified.

The EAT overturned this tribunal decision. He was disabled. The tribunal should have had regard to the effect of his impairments, not their cause. The impairment may be physical or mental (indeed they may overlap), but it need not be shown to be caused by something physical or mental. So in this case it did not matter that there was no suggestion of any mental illness causing the functional overlay. However if the genuineness of the symptoms is at issue (it wasn’t in this case) the absence of a recognised cause may have evidential value in deciding whether the symptoms are genuine.

The EAT accepted that “it is not necessary for a Tribunal to categorise an impairment as physical or mental as if they were watertight definitions. They cannot be seen as if in two separate silos. It is not always possible, nor it is necessary, to categorise a condition as either one or the other.”

Plainly in this case the claimant had both “physical” and “mental” impairments. “Chronic fatigue syndrome may mix the two; bowel and stomach problems, and knee problems, are physical; anxiety and depression are mental.”

EU Court of Justice decisions such as, on obesity, Fag og Arbejde, acting on behalf of Kaltoft v Kommunernes Landsforening (bailii.org), 2014 (commonly known as Kaltoft), and Carlos Enrique Ruiz Conejero v Ferroser Servicios Auxiliares SA (bailii.org), 2018, have similarly focused on whether there is sufficient limitation of capacity entailed by the obesity etc (hindering the person’s full and effective participation in professional life on an equal basis, as set out in Ring), and have said that the origin of the disability does not matter.

Ministry of Defence v Hay (bailii.org), EAT, 2008
The medical evidence was that impairments attributable to the claimant’s tuberculosis alone would have lasted for less than 12 months. However the EAT held the tribunal was entitled to hold that he was disabled by reason of a constellation of symptoms not medically attributed to TB. The statutory approach was “self evidently a functional one directed towards what a claimant cannot, or can no longer, do at a practical level”.

The EAT said that “the term ‘impairment’ bears its ordinary and natural meaning. It may be an illness. It may result from an illness. It is not necessary to consider the cause of it.”

It was accepted that a tribunal was entitled to regard as disabled someone who suffered from a combination of impairments with different effects, to different extents, over periods of time which overlapped.

A6 It may not always be possible, nor is it necessary, to categorise a condition as either a physical or a mental impairment. The underlying cause of the impairment may be hard to establish. There may be adverse effects which are both physical and mental in nature. Furthermore, effects of a mainly physical nature may stem from an underlying mental impairment, and vice versa.

A7. It is not necessary to consider how an impairment is caused, even if the cause is a consequence of a condition which is excluded. For example, liver disease as a result of alcohol dependency would count as an impairment, although addiction to alcohol itself is expressly excluded from the scope of the definition of disability in the Act. What it is important to consider is the effect of an impairment, not its cause– provided that it is not an excluded condition. …
2011 guidance, para A6 and A7

McNicol v Balfour Beatty Rail Maintenance, Court of Appeal, 2002
“It is left to the good sense of the tribunal to make a decision in each case on whether the evidence available establishes that the applicant has a physical or mental impairment with the stated effects. Such a decision can and should be made without substituting for the statutory language a different word or form of words in an ambitious and unnecessary attempt to describe or to define the concept of ‘impairment’.”

A bit of legislative history

The legislative history indicates that “physical or mental” is intended to have a wide meaning.

In the Standing Committee Debates considering the Disability Discrimination Act 1995 (Hansard, H.C., Session 1994-95, Standing Committee E, cols 71,72, 101) the then Minister of Social Security and Disabled People, William Hague, made it clear that physical and mental are intended to be seen in their widest sense and should comprehensively cover all forms of impairment.

20th anniversary of stammeringlaw, 1999-2019