by Kate Russell

What does ‘substantial’ mean?

The adverse effect on normal day-to-day activities must be a substantial one. It must be more than a condition which may be considered to be minor or trivial. It will be for the Court to consider whether an impairment is ‘substantial’. This will be satisfied if the impairment can be shown to be ‘more than minor or trivial’, for example if it takes longer to do daily tasks, such as getting dressed.

Factors to consider

1. Time to carry out an activity

The time taken by a person with an impairment to carry out a normal day-to-day activity should be considered when assessing whether the impairment’s effect is substantial. Compare it with the time it might take a person who does not have the impairment to complete an activity.

Another factor to be considered is the way in which a person with that impairment carries out a normal day-to-day activity compared with the way that the person might be expected to carry out the activity if he does not have the impairment.

2. Cumulative effects of the impairment

Taken in isolation, an impairment might not have a substantial adverse effect on a person’s ability to undertake a particular day-to-day activity, but its effects on more than one activity, taken together, could result in an overall substantial adverse effect.

For example, a person whose impairment causes breathing difficulties may, as a result, experience minor effects on the ability to carry out a number of activities, such as getting washed and dressed, preparing a meal, or travelling on public transport. But taken together, the cumulative result would amount to a substantial adverse effect on his ability to carry out these normal day-to-day activities.

3. Environmental factors

Environmental conditions may exacerbate the effect of an impairment. Factors such as temperature, humidity, lighting, the time of day or night, how tired the person is, or how much stress he is under, may have an impact on the effects. When assessing whether adverse effects are substantial, the extent to which such environmental factors are likely to exacerbate the effects should also be considered.

The focus here is on what the worker cannot do or can only do with difficulty. Just because the employee can carry out a number of day-to-day activities, this doesn’t mean that he is not substantially affected.


Mr Billett who was in the army sustained a non-freezing cold injury to his feet. He successfully sued his employer for failing to supply suitable footwear, which exposed him to a permanent sensitivity to cold.

On appeal, the Court confirmed that the focus should be on what Mr Billett was unable to do, rather than what he could do. He was restricted in carrying out many activities, such as gardening, DIY, rugby and swimming, especially when the weather was cold. The Court determined that this was more than ‘trivial’.

4. Effects of behaviour

In deciding what is substantial, consider how far a person can reasonably be expected to modify his behaviour to prevent or reduce the effects of an impairment on normal day-to-day activities. If he can reasonably be expected to behave in such a way that the effect of the impairment doesn’t have a substantial adverse effect on his ability to carry out normal day-to-day activities, he would no longer meet the definition of disability. For example, when considering modification of behaviour, it would be reasonable to expect a person who has back pain to avoid extreme activities, such as parachuting. It would not be reasonable to expect him to give up, or modify, more normal activities that might exacerbate the symptoms, such as moderate gardening, shopping, or using public transport.


Mr Stoute suffered from Type 2 diabetes. This could be controlled by following a diabetic diet which involved abstaining from sugary food and drinks. Failure to do so could result in a hypoglycaemic episode.

When Mr Stoute was dismissed he brought claims for disability discrimination and a failure to make reasonable adjustments.

The EAT held that the employment tribunal was wrong to conclude that Mr Stoute is disabled. It did not agree with the employment tribunal’s view that abstaining from sugary foods/drinks could be regarded as “treatment or correction” or a substantial interference with normal day-to-day activities. If this were the case, it could lead to open floodgates for claims by those who have to restrict their diet (for example, those with nut allergies or lactose intolerance).

The EAT pointed out paragraph B7 of the Equality Act Guidance, which states:

“In some instances, a coping or avoidance strategy might alter the effect of the impairment to the extent that they are no longer substantial and the person would no longer meet the definition of disability.”

The judgment in the Stoute case confirms that having Type 2 diabetes in itself does not automatically mean that a person is disabled and illustrates that even medically well-recognised conditions will not always amount to a disability. There has been some criticism at the way in which it was reached; it appears to suggest that those conditions controlled by diet would not amount to a disability.

The EAT in Stoute did not refer to B14 of the EqA Guidance which says:

“...the case of someone with diabetes which is being controlled by medication or diet should be decided by reference to what the effect of the condition would be if he or she were not taking that medication or following the required diet.”

It is also important to note that the EAT accepted that medicated diabetes sufferers (Type 1 or Type 2) are regularly considered to be disabled for the purposes of the EqA.

You have to take into account a situation where a person avoids doing things which, for example, cause pain, fatigue or substantial social embarrassment or avoids them because of a loss of energy and motivation. It would not be reasonable to conclude that a person who employed an avoidance strategy was not a disabled person. In determining a question as to whether a person meets the definition of disability, it is important to consider the things that a person cannot do, or can only do with difficulty, rather than focusing on those things that a person can do.

For example, a woman with a persistent stammer uses coping strategies to manage her condition, such as avoiding using the telephone, not giving verbal instructions at work, limiting social contact outside her immediate family, and avoiding challenging situations with service providers. It may not be readily obvious that she has an impairment which adversely affects her ability to carry out normal day-to-day activities. In determining whether she meets the definition of disability, you should consider the extent to which it is reasonable to expect her to place such restrictions on her working and domestic life.