Around 800,000 self-employed people in the UK who started working for themselves between 2015 and 2024 may have gaps in their National Insurance (NI) record, potentially reducing their State Pension entitlement by thousands of pounds. The issue arises because many failed to notify HMRC of their self-employed status using the CWF1 form, even if they registered for self-assessment.
Who Is Affected and Why
According to HMRC, the problem stems from a requirement introduced in 2015 that newly self-employed individuals must both register for self-assessment and separately inform HMRC by submitting the CWF1 form. Those who completed the self-employed section of their tax return but did not submit the CWF1 form may not have paid the correct amount of Class 2 National Insurance contributions. As a result, their NI record could show incorrect gaps, affecting their eligibility for the full State Pension.
HMRC estimates that approximately 800,000 people have been impacted, including around 160,000 individuals who have already reached State Pension age or will do so within the next two years. For self-employed workers, entitlement to the full new State Pension—currently worth £241.30 per week—generally requires at least 35 qualifying years of NI contributions, though some individuals may need more depending on their circumstances.
National Insurance Contributions for the Self-Employed
Self-employed people build up qualifying years through Class 2 National Insurance contributions, with the amount payable depending on annual earnings. Those earning less than £7,105 a year can choose to make voluntary Class 2 contributions to prevent gaps. For the 2026/27 tax year, these voluntary payments cost £3.65 per week, totalling around £189.80 for a full year. Anyone with annual profits of £7,105 or more receives Class 2 NI credits automatically, protecting their State Pension record. Depending on earnings, they may also have to pay Class 4 NI contributions, which do not count towards State Pension entitlement.
Before 6 April 2024, self-employed workers with profits above a set threshold—£12,570 during the 2023/24 tax year—were also required to pay mandatory Class 2 NI contributions. That requirement was removed from the 2024/25 tax year onwards.
HMRC's Response and Next Steps
HMRC has confirmed that only a minority of self-employed registrations between 2015 and 2024 have been affected, but this still amounts to around 800,000 individuals. The department stated that the CWF1 form was needed "for Class 2 to be assessed and collected correctly." Improvements introduced from the 2024/25 tax year mean the correct contributions will now be added even without the CWF1 form, fixing the issue going forward.
Letters notifying affected individuals began being issued in July 2026, with HMRC sending them in phases to ensure sufficient resources are available to help those who get in touch. Those already at State Pension age or reaching it within two years should expect to receive a letter by summer 2027. Everyone else affected is expected to start receiving letters from spring 2027 onwards.
Anyone contacted by HMRC will be directed to speak with the Department for Work and Pensions (DWP), which will help them understand whether the issue has affected their State Pension entitlement. The DWP will also advise whether making additional NI contributions to fill gaps would be worthwhile.
Opportunities to Fill Gaps
Although people are normally only able to fill NI gaps going back six tax years, HMRC has confirmed that those affected by this issue will be allowed to pay voluntary contributions for earlier years dating back to 2015, using the original contribution rates. The Government is also updating the Gov.uk State Pension Forecast tool, which allows people to check their State Pension entitlement and identify opportunities to increase it by filling NI gaps.
From spring 2027, self-employed people will also be able to check whether they have NI gaps related to this issue or other reasons, see whether paying to fill those gaps would increase their State Pension, and make voluntary NI contributions through the online service.
No Immediate Action Required
Until they receive a letter, HMRC is advising people not to take any action. The department says contacting it or attempting to complete the CWF1 form retrospectively "could disrupt" the process of resolving the issue for everyone affected. HMRC assured that it will contact all affected individuals directly.
