Between 25 May and 11 June 2025, HMRC experienced a technical issue that caused some employee tax code updates (P6 notices) to go missing. If your staff have received unexpected tax code letters, or if payslips looked unusual in June, this could be why.
Let’s walk through what happened, how to check if you're affected, and what to do next.
What Actually Happened?
HMRC confirmed in a letter dated 3 July 2025 that a system error prevented some P6 notices from reaching employers. These are the notices that inform payroll teams about tax code changes for employees.
The issue has now been fixed, and corrected tax codes are available to download. It’s important to know whether your team or payroll provider missed anything.
Here is a copy of the letter we received yesterday, dated 3rd June.
HMRC Tax Code Error – Are You Affected?
You might be affected if:
- Employees received P6 notices but your payroll software didn’t reflect the change.
- Payslips for June 2025 show higher or lower than expected tax deductions.
- Your payroll team didn’t apply any new tax codes in June.
Ask your team or payroll provider:
- Have we received any corrected P6 notices?
- If they know if any employees were impacted in June?
- Have the corrected codes been received and will they now been applied?
What This Means for Your Staff
In most cases, any over or underpayment of tax will be automatically adjusted in your employee’s next payslip.
But there are exceptions. HMRC may not be able to fully fix every case right away. If not, they’ll either:
- Send a new code later in the tax year, or
- Reconcile everything at year-end.
HMRC advise, employees and employers do not need to call HMRC, but they may want to check their tax code online or via the HMRC app for peace of mind which can be downloaded here:
Do You Need to Do Anything?
Yes — but only a few simple steps:
✅ Download and apply the corrected tax codes (P6 notices) before your next payroll run.
✅ Check your software or agent dashboard for any missed P6s.
✅ Reassure employees that the issue is known and being fixed.
You do not need to:
- Re-run or adjust June payroll.
- Contact HMRC.
- Make any manual corrections or submit extra reports.
What If HMRC Doesn’t Fix It?
In rare cases where the wrong code continues to be used:
- The employee may keep overpaying tax.
- HMRC will try to fix it, but if not, they’ll issue a refund or new code later.
- Employees can call HMRC on:
- Telephone: 0300 200 3300
- Outside UK: +44 135 535 9022
- Opening times: Monday to Friday: 8am to 6pm. Closed bank holidays.
If this causes financial hardship, employees can submit a complaint via GOV.UK and may be eligible for redress. You might want to help guide them through that process or watch the HMRC You Tube video on how to check your tax code;
What Else Should Employers Do?
As a business owner or payroll technician:
- Let your HR or payroll team know about the issue.
- Ask employees if they’ve had tax code notices from HMRC recently.
- Keep a record of any concerns raised, especially if a complaint might be needed later.
- Consider sending out a short internal update to staff explaining what happened and what to expect.
FAQs
It’s a tax code notification HMRC sends to employers when an employee’s tax code changes.
No. Only some employers were affected. But it’s worth checking with your payroll team.
No need. HMRC has asked employers not to get in touch unless specifically instructed.
If they experience genuine financial hardship as a result, yes, through HMRC’s complaints process.
Need Help Sorting This Out?
If you’re not sure whether you’ve been affected or if you want support applying the corrected tax codes, we can help.
We work with hundreds of businesses large and small each month and stay on top of changes like this, so you don’t have to.
If you found this article useful, below are some other articles that may be of interest:
