Harnett Accontants

Harnett & Co | Chartered Accountants, Kingston upon Thames
Global House Business Centre 1 Ashley Avenue Epsom Surrey KT18 5AD
ICAEW Authorised Practice
Accountancy

– Whose Fault Is Underpaid Tax?

want to remind you of this great tax tip originally brought to you by Harnett Accountants Hammersmith earlier this month.

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Reviewed for 2026/27: All tax figures and HMRC rules in this article reflect current guidance for the 2026/27 tax year.

Key Considerations

Have you received a tax calculation (on form P800) which shows you owe tax that you thought had been collected under PAYE? Every year the Tax Office undertakes a ‘PAYE reconciliation’ to check whether the tax collected from pensions and salary under PAYE was the correct amount. Where a taxpayer has a number of jobs or several pensions in a year, the PAYE system can get it wrong, leaving tax underpaid.

We can help you check any form P800 you receive, but we need to see the PAYE codes issued to you for the tax year, and payslips from your employer or pension provider to check what PAYE codes they have used. Where the employer/pension provider has not used the correct PAYE code and this causes any tax not to be collected, it remains their responsibility, not yours.

Unfortunately the Taxman is ignoring this piece of law and is demanding payment of the underpaid tax from employees and pensioners, where the error lies with the employer/pension provider. We can help you challenge the Taxman on this point.

Sometimes the fault lies with the Taxman who has ignored information you or your employer have provided on more than one occasion. The Tax Office may also have let tax arrears to build up over two or more years without telling you. If either of these situations apply, you can ask the Taxman to write-off the tax owing under Extra Statutory Concession A19. The Taxman is very reluctant to use this concession, but we can help argue your case.

If you need advice about taxes, or help to make sure that you are paying exactly the right amount of tax, and running your business in the most tax efficient way possible, contact our accountants in Wimbledon and we will arrange a free, one hour, no obligation consultation. You can contact us through our website or on 020 8977 3883. Also you can . Additionally, you can keep reading our daily blogs.

📌 Important: Tax rules change regularly. Always verify current figures at gov.uk/hmrc or speak to a qualified accountant.
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Harnett and Co are ICAEW chartered accountants in Kingston upon Thames, Surrey. We give clear, practical advice to businesses and individuals across West London and Surrey. Book a free consultation today.