CH206225 - How to do a compliance check: starting a compliance check: pre-population of online Self-Assessment Returns
Source: gov.uk (2025-09-01)


This page and chapter are under review as the relevant content is also published in the technical guidance chapters of the Compliance Handbook (https://www.gov.uk/hmrc-internal-manuals/compliance-handbook), within Compliance checks factsheets (https://www.gov.uk/government/collections/hm-revenue-and-customs-compliance-checks-factsheets) and in Compliance checks guidance (https://www.gov.uk/guidance/hmrc-compliance-checks-help-and-support). If you use particular pages regularly, please email xxx@xxx.xx (mailto:xxx@xxx.xx) to let us know the specific content you find useful.

This guidance explains:
- how pre-population of Income, Allowances, Benefits and Deductions (IABD) data might impact customers when completing their SA Returns online
- how you can identify if a customer’s return contains pre-populated data held by HMRC
- what factors you should consider as part of any compliance intervention.
How pre-population of IABD data works

To help customers complete their 2015-16 online SA returns, under certain conditions designated fields will be pre-populated with data provided from other sources – for example, PAYE Service (NPS).

The pre-populated data will be presented to the customer via the ‘Information we hold about you’ page. The page explains about pre-population, confirms what fields have been pre-populated and advises the customer that they’ll have the opportunity to amend or delete the relevant sections if they believe they are incorrect. The customer will be asked to tick the mandatory check box ‘I have viewed the information HMRC holds about me’ before they can start to file their return online.

For customers who file their return through HMRC's Online Service, entries will have been pre-populated that relate to:
- designatory details - such as, name, UTR, NIN0, address
- underpayments coded out
- small debts coded out
- State Pension
- Student Loan indicator
- Local authority – where a person is claiming Blind Person’s Allowance.
The new data supplied includes:

Other benefits

Expenses payments received and balancing charges

The source data used for pre-population is refreshed on a daily basis, this minimises any risk that the customer is given out of date Information.

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Factors to consider as part of any compliance intervention

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If the customer accepted the pre-population offered, then a discrepancy should not arise. (This content has been withheld because of exemptions in the Freedom of Information Act 2000)
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If the customer acknowledges that they changed or deleted the data offered, you will need to establish the reasons why they made the changes. You will need to ask the customer for further information to understand how any discrepancy has arisen. It is good practice to start by establishing basic information as this will help prevent disagreements later about how and why the discrepancy occurred.

For either of these scenarios here are some questions to ask:
- Why did you accept the pre-populated data when you knew it was wrong?
- What was the reason you didn’t advise HMRC that the pre-populated figure we provided was wrong?
- Why did you think that the pre-populated information was wrong?
- Why did you make the changes to the pre-populated field?
- What did you do to establish that the amount you included in the return was the correct amount?
You can find further examples of questions to establish behaviour at CH402301 (https://www.gov.uk/hmrc-internal-manuals/compliance-handbook/ch402301).

Before you ask the customer about their behaviour, you must issue the HRA and penalty factsheets and explain the process to them, see CH402350 (https://www.gov.uk/hmrc-internal-manuals/compliance-handbook/ch402350).