Fit Notes: A UK Employer Guide

Executive Summary

Fit notes are medical statements that confirm an employee's incapacity for work and outline whether they may be fit for work with support. For SMEs, they are a key part of managing sickness absence, but they are often misunderstood. A fit note is not a return-to-work plan, not a list of required adjustments and not a guarantee of when someone will be back. It is evidence of incapacity and a starting point for a conversation. Understanding what fit notes do (and don't) tell you helps SMEs act fairly, avoid unnecessary medical detail and support employees safely.

What this means for your business

Fit notes are designed to support work, not restrict it. They provide:

Confirmation that the employee is not fit for work.
An option for the GP to indicate that the employee may be fit with support.
Broad functional suggestions (e.g., 'avoid heavy lifting', 'reduce stress').
A timeframe for review.

They do not:

Prescribe specific duties.
Require employers to implement every suggestion.
Provide diagnosis or detailed medical information.
Override health and safety responsibilities.
Guarantee a return date.

Fit notes guide the conversation. They don't replace it.

Legal and Statutory Requirements

Fit notes provide evidence of incapacity for Statutory Sick Pay purposes. (Gov.uk, 2024)
GPs can advise that an employee 'may be fit for work' with adjustments, but employers are not legally required to implement adjustments that are not reasonable or safe. (NHS, 2023)
Employers must consider reasonable adjustments for disabled employees. (Equality Act 2010, c.15)
Employers must protect employee health and safety, including during return-to-work transitions. (HSE, 2024)
Fit notes do not require disclosure of diagnosis; evidence should be proportionate. (ACAS, 2023)

Fit notes sit within this framework but do not dictate operational decisions.

What managers can do

SMEs often feel uncertain about how to interpret fit notes. These principles help managers use them well without drifting into medical territory:

Focus on function, not diagnosis. What the employee can do is more important than the label for their condition.
Use the fit note as a conversation starter. Ask the employee how the GP's comments translate into day-to-day work.
Be proportionate with evidence. You rarely need more than the fit note unless symptoms are long-term or unclear.
If the GP suggests adjustments, explore them. Don't assume they're mandatory. They are guidance, not instructions.
If adjustments aren't workable, explain why and explore alternatives.
Avoid making assumptions about recovery speed. The 'review date' is not a guaranteed return date.
Document key points. This protects both sides and keeps the process fair.

These principles help SMEs act confidently without over-medicalising the situation.

Examples

'May be fit for work' with stress-related symptoms: The GP suggests reduced workload and a gradual return. The manager and employee discuss which tasks feel manageable and agree a short, reviewable plan. If certain tasks trigger symptoms, both sides agree to adjust the plan rather than forcing a fixed timetable.
Musculoskeletal injury with restrictions: The fit note advises avoiding heavy lifting. The manager and employee identify which duties are safe and which should be paused. They agree a review point aligned with the fit note's timeframe, ensuring the employee isn't pushed into unsafe tasks.
Fluctuating condition with variable capacity: The GP notes that symptoms may vary. The manager and employee agree that on days when symptoms flare, the employee will focus on core tasks and flag if capacity drops. This avoids performance pressure and supports a sustainable return.

Common Pitfalls

SMEs often run into issues when they:

Treat the fit note as a set of instructions.
Assume the GP's suggestions must be implemented exactly.
Ask for diagnosis or detailed medical information.
Rely solely on the fit note without speaking to the employee.
Treat the review date as a guaranteed return date.
Ignore Equality Act implications when symptoms persist.
Assume 'may be fit for work' means the employee must return immediately.

Avoiding these pitfalls keeps the process fair, safe, and legally sound.

When to Consider Occupational Health Input

The fit note is vague or symptoms are long-term.
The employee is struggling to return despite supportive adjustments.
There is uncertainty about what duties are safe.
Adjustments are unclear, disputed, or not working.
There may be Equality Act implications.
The manager needs clarity on functional impact rather than diagnosis.

Bringing It All Together

Fit notes are a useful tool, but they are only one part of managing sickness absence. They provide evidence and broad guidance, but the real value comes from calm, collaborative conversations about what the employee can safely do. A proportionate, flexible approach helps SMEs support recovery, reduce risk, and maintain fairness.

References

ACAS (2023) If a fit note says 'might be fit for work'. Available at: https://www.acas.org.uk/fit-notes-and-proof-of-sickness/if-a-fit-note-says-might-be-fit-for-work (Accessed: 25 April 2026).
Equality Act 2010, c.15. London: The Stationery Office. Available at: https://www.legislation.gov.uk/ukpga/2010/15/section/20
HSE (2024) Sickness absence. Health and Safety Executive. Available at: https://www.hse.gov.uk/sicknessabsence/ (Accessed: 25 April 2026).
Gov.uk (2024) Fit notes: guidance for employers and line managers. Available at: https://www.gov.uk/government/publications/fit-note-guidance-for-employers-and-line-managers (Accessed: 25 April 2026).
Gov.uk (2024) Statutory Sick Pay (SSP). UK Government. Available at: https://www.gov.uk/statutory-sick-pay (Accessed: 25 April 2026).

OH Sam is a self-serve tool for practical workplace health advice and support. It does not replace clinical, legal or specialist occupational health advice.