Underpayment Formal Complaint Letter: Free Template and What to Include

If you need to formally complain to your employer about being paid below minimum wage, a written letter is the recommended first step — it creates a clear record and shows you're pursuing the matter formally. Below is what a strong underpayment formal complaint should include.

What this letter needs to cover

• State the correct NMW rate for the workers age and category
• Calculate the underpayment with figures
• State this is unlawful under the National Minimum Wage Act 1998
• Request immediate correction and repayment of arrears
• Warn that failure to correct may result in a report to HMRC

Calculating whether you're genuinely being underpaid

Minimum wage underpayment isn't always obvious from your payslip alone — it can result from unpaid trial shifts, mandatory unpaid training, deductions for uniform or equipment that take you below the threshold, or simply an hourly rate that's below the correct rate for your age band.

What to include before you send it

• Your age band and the correct minimum wage rate that should apply
• Your actual hourly rate, and how you've calculated the shortfall
• The period you believe this has been happening
• A request for back payment of the difference

Deductions that can push you below minimum wage without you realising

Certain deductions — for example, for uniform costs where you're required to buy your own from a specific supplier — can effectively reduce your pay below minimum wage even if your headline hourly rate looks correct. It's worth checking your actual take-home pay against hours worked, not just your stated rate.

Frequently Asked Questions

How far back can I claim underpaid wages?
Claims for unlawful deduction from wages generally need to be brought within 3 months minus 1 day of the last deduction (6 months minus 1 day in England, Wales and Scotland where the wages were paid on or after 1 October 2026), though a series of deductions can sometimes extend this — it's worth acting promptly regardless.

What if my employer says apprentices or under-21s are paid differently?
Different minimum wage rates do apply by age band and for apprentices who are under 19 or in the first year of their apprenticeship — it's worth confirming which specific rate should apply to your situation.

[Your Name]
[Your Address]
[Your Postcode]
[Your Phone Number]
[Your Email Address]
[Name of Contact / HR Department]
[Company Name]
[Company Address]
[Company Postcode]
[Date]

Dear [Name of Contact, or "the HR Manager"],

Subject: Formal Grievance – Underpayment of the National Minimum Wage

I am writing to formally raise a grievance about my pay. I believe I am being paid less than the National Minimum Wage I am legally entitled to.

My current pay is £[e.g. 11.00] an hour. I am aged [your age] [Optional: and I am an apprentice in the first year of my apprenticeship / an apprentice aged 19 or over who has completed my first year]. The legal minimum rate for me is £[current rate for your age or status] an hour.

I believe I am underpaid because:
• [e.g. My hourly rate is below the rate for my age group]
• [e.g. I am not paid for compulsory time at work before or after my shift, such as setting up, security checks or staff meetings]
• [e.g. I am not paid for compulsory training time]

Under the National Minimum Wage Act 1998, I must be paid at least the minimum wage for all the time I work.

Please investigate, correct my pay, and pay me all arrears as soon as possible. Please also send me a breakdown of my working hours and how my pay was worked out.

Please reply within [e.g. 14] days to arrange a formal grievance meeting.

Yours sincerely,

[Your Signature]
[Your Printed Name]