Understanding “Reasonable”: Factors in UK Employment Tribunals
When disputes about reasonable adjustments reach an employment tribunal, the question is rarely emotional. It is analytical.
Tribunals do not ask whether an employer meant well. They ask whether the employer acted reasonably, based on evidence, context, and the purpose of the Equality Act.
For HR and legal readers, this matters because tribunal reasoning is consistent, even when outcomes differ. Understanding the factors tribunals rely on is the difference between a defensible decision and an exposed one.
The tribunal’s starting point
Tribunals start from the statutory duty in the Equality Act 2010:
https://www.legislation.gov.uk/ukpga/2010/15/section/20
The duty is to take reasonable steps to remove a substantial disadvantage caused by:
a workplace provision, criterion, or practice
a physical feature
the absence of an auxiliary aid or service
The adjustment does not need to be perfect. It needs to be reasonable in context.
What tribunals actually assess
Across tribunal decisions, a small set of factors appears repeatedly. No single factor decides the case. Tribunals look at the overall balance.
1) Effectiveness: did the adjustment reduce the disadvantage?
This is the most important factor.
Tribunals ask:
What was the actual disadvantage?
Would the proposed adjustment have removed or reduced it?
Did the employer properly understand the barrier?
Adjustments that do not address the real problem are often deemed unreasonable, even if they sound supportive.
Conversely, refusing an adjustment that clearly would have reduced the disadvantage is high risk.
2) Practicality and implementation
Tribunals examine whether the adjustment was realistically achievable.
This includes:
how quickly it could be implemented
whether it required complex restructuring
whether temporary or trial arrangements were possible
Importantly, tribunals are sceptical of arguments that something was “too difficult” when no trial was attempted.
3) Cost relative to resources
Cost is relevant, but never in isolation.
Tribunals look at:
the absolute cost
the employer’s size and financial resources
whether the cost was one-off or ongoing
whether funding or alternatives were explored
Large employers are expected to absorb costs that would be unreasonable for small ones. Refusals based on cost are closely scrutinised if no exploration of alternatives took place.
4) Availability of external support
Tribunals routinely consider whether Access to Work or similar support could have funded or reduced the cost of an adjustment:
https://www.gov.uk/access-to-work
Employers who refuse adjustments without considering available funding weaken their position significantly.
5) Impact on the business and others
Tribunals will consider operational impact, but they draw a sharp line between:
genuine operational disruption, and
inconvenience or team preference
Arguments based on “fairness to others” or “setting a precedent” carry little weight unless they are tied to concrete operational evidence.
6) Health and safety
Health and safety can justify refusal, but only where:
the risk is specific and evidenced
mitigation options were explored
the risk could not reasonably be managed
Generalised safety concerns rarely succeed without assessment.
7) The employer’s process and reasoning
Tribunals look closely at how decisions were made.
They examine:
whether the employer engaged with the employee
whether alternatives were discussed
whether decisions were explained
whether reasoning was recorded
A reasonable decision made through a poor process is still vulnerable.
What tribunals are unimpressed by
Certain arguments appear regularly in unsuccessful defences.
Tribunals consistently reject:
“We’ve never done this before”
“Other employees wouldn’t like it”
“The manager didn’t think it was necessary”
“The employee didn’t ask clearly enough”
“We didn’t have a policy”
These are opinions, not evidence.
Case patterns tribunals often see
Without naming individual cases, some patterns recur across tribunal outcomes.
Adjustments often found reasonable
flexible start or finish times
temporary workload changes
remote or hybrid working where the role allowed
written instructions or altered communication methods
low-cost equipment
Adjustments often lawfully refused
requests removing the core function of a role
adjustments creating unmitigated safety risks
high-cost changes with no exploration of funding or alternatives
The deciding factor is rarely the adjustment itself. It is whether the employer could show they thought properly and acted proportionately.
Documentation matters more than people expect
Tribunals place significant weight on written records.
They ask:
What was requested?
What was considered?
Why was a decision made?
What alternatives were explored?
Where there is no record, tribunals often infer that proper consideration did not take place.
This is why informal, undocumented handling is risky, even when intentions are good.
Why tribunal reasoning matters for employers now
Most employers will never face a tribunal. But tribunal reasoning sets the standard that employers are expected to meet.
ACAS guidance reflects these same principles and is often used as a benchmark for reasonableness in practice:
https://www.acas.org.uk/reasonable-adjustments
If your process would not make sense to a neutral third party, it is unlikely to survive scrutiny.
Where Mosaic fits into tribunal expectations
Mosaic is designed around the exact factors tribunals look for.
It helps employers:
clearly identify the disadvantage
explore and record adjustment options
document cost, practicality, and alternatives
note funding checks such as Access to Work
create a consistent written record
demonstrate that decisions were reasoned, not reactive
Mosaic does not guarantee outcomes.
It ensures the process aligns with how tribunals actually assess reasonableness.
That alignment is what protects organisations.
Next Steps
Read more here
FAQs: how tribunals decide reasonable adjustments
Is cost the main factor tribunals consider?
No. Cost is one factor, but effectiveness and proportionality carry more weight.
Do tribunals expect employers to agree every adjustment?
No. They expect employers to engage, consider evidence, and aim to remove the disadvantage.
Does a good process matter as much as the decision?
Yes. Poor process undermines otherwise reasonable decisions.
