HMRC Spots Discrepancies Using Data Analytics
17th August 2026
HMRC is stepping up its use of data analytics and “nudge letters” to identify individuals who may have omitted income, gains or other relevant information from their personal tax returns. HMRC is increasingly able to spot discrepancies and contact taxpayers before launching a formal enquiry.
They do this by comparing Self Assessment returns against:
- Data received from banks,
- Digital platforms,
- Overseas tax authorities,
- Property records
- Other third parties
What should you do if you discover an omission?
The worst option is to ignore it. The best option is to contact your local Whitings LLP office and speak to one of our experts.
HMRC actively encourages taxpayers to come forward voluntarily if they realise information has been missed from a tax return. Making an unprompted disclosure often results in lower penalties than waiting for HMRC to find the error. In more serious cases, voluntarily correcting mistakes can significantly reduce the risk of further enforcement action.
Start by reviewing the return carefully and identifying exactly what was omitted. Common issues include rental income, offshore bank interest, investment income, capital gains and earnings from online platforms. Gather supporting records to quantify any additional tax that may be due. If an amendment is still possible, correct the return as soon as possible with the help of Whitings LLP. Where amendment deadlines have passed, HMRC provides disclosure facilities that allow taxpayers to report unpaid tax voluntarily and bring their affairs up to date.
The key message
HMRC’s data-matching capabilities are stronger than ever. If you think information has been missed from a personal tax return, act quickly, review your position, seek professional advice from us where necessary and make a voluntary disclosure before HMRC contacts you. Early action is usually the most cost-effective and least stressful route to resolution, and can lead to a reduction in penalties that they will apply.
Disclaimer - All information in this post was correct at time of writing.
