HMRC has begun writing to as many as 800,000 self-employed people whose National Insurance records may contain gaps. The letters, reported by ICAEW, are not payment demands but a chance to correct missing qualifying years that could otherwise cut State Pension entitlement.
The numbers behind the exercise:
- HMRC’s estimate, reported by ICAEW, runs to 800,000 people, of whom around 160,000 have already reached State Pension age or are within two years of it.
- Those affected registered as self-employed at some point from 2015 to early March 2024 without submitting form CWF1.
- Letters began arriving in July 2026, in stages: those at or near State Pension age by summer 2027, everyone else from spring 2027.
- Gaps may be filled back to the 2015 to 2016 tax year, beyond the usual six-year limit for voluntary contributions.
- A full year of voluntary Class 2 costs £189.80 at 2026 to 2027 rates, against £956.80 for Class 3.
Why these self-employed National Insurance gaps occurred
From the 2015 to 2016 tax year, Class 2 contributions for most self-employed earners have been assessed through Self Assessment. But registering for Self Assessment was not enough on its own: a separate notification, form CWF1, brought the earner into the Class 2 system.
ICAEW reports that HMRC has identified an issue affecting people who started working for themselves between 2015 and early March 2024.
Where no CWF1 was submitted, HMRC accepts those taxpayers “could have gaps in their NIC record” — including people who did complete the self-employment section of their return.
Ross Martin reports that many of those affected already held a Unique Taxpayer Reference and began trading without a CWF1, so HMRC’s records did not show Class 2 was due.
The same report points to two further routes into a gap: Class 2 settled late, after the 31 January due date, and payments that went to clear a tax bill before they reached the contributions.
HMRC has confirmed the problem is fixed from the 2024 to 2025 tax year onwards, with contributions now added without a CWF1.
What the HMRC letters say, and who receives one
That upper estimate spans a nine-year window and is not a count of confirmed shortfalls. HMRC has stressed that only a minority of those who registered in the period are affected.
The order runs by proximity to State Pension age, oldest first, and MoneySavingExpert reports the staggering is deliberate so HMRC can resource the responses.
A letter is not confirmation of a shortfall either. Some recipients may already hold enough qualifying years from employment, earlier self-employment or National Insurance credits, so further contributions would add nothing.
What a missing qualifying year is worth
Under the Pensions Act 2014, each qualifying year on a record buys one 35th of the full new State Pension, and GOV.UK sets the floor for receiving anything at all at 10 qualifying years.
People contracted out before 2016 may need more than 35 years to reach the full figure.
The full new State Pension is £241.30 a week in the 2026 to 2027 tax year, about £12,548 a year, after April’s 4.8% uprating.
A single qualifying year is therefore worth roughly £6.89 a week, or £358 a year, for life — in the region of £7,000 across a 20-year retirement at today’s rates.
An unusual chance to reach back a decade
Voluntary contributions can normally only fill gaps in the previous six tax years. This exercise is unusual in allowing eligible people to pay for years as far back as 2015 to 2016.
Class 2 is also the cheapest voluntary class. At the 2026 to 2027 rates on GOV.UK, a full year costs £3.65 a week, or £189.80, against £18.40 a week, or £956.80, for Class 3.
MoneySavingExpert reports that affected people should be able to pay earlier years at the original rates for those years, rather than the current-year rate that normally applies.
Two wider changes are worth separating out. Class 2 stopped being a mandatory charge for most self-employed people from 6 April 2024, and profits above the Small Profits Threshold are now treated as though contributions had been paid.
Voluntary Class 2 for periods spent abroad closed to new applications on 6 April 2026, leaving Class 3 as the route from 2026 to 2027 onwards. GOV.UK confirms that contributions payable for periods abroad before that date are unaffected.
Neither change alters the historic years this exercise covers. The cost of getting Class 2 wrong was illustrated at the First-tier Tribunal in Mark Gadsden v HMRC.
The taxpayer was found to have exercised due care and diligence, and won the right to have his late-paid Class 2 contributions treated as paid for State Pension purposes.
What this means for you
If you worked for yourself between 2015 and early 2024, a few minutes checking your own record could be worth several hundred pounds a year in retirement.
What to do now
- Check your State Pension forecast. Get your forecast on GOV.UK to see your projected weekly amount, the qualifying years you hold, and whether topping up would help. Your contribution history sits in your Personal Tax Account.
- Hold off on contacting HMRC about this issue, and do not submit a CWF1 for a past year. HMRC’s position, reported by MoneySavingExpert, is that doing so “could disrupt” the correction work, and that affected people are contacted directly. A GOV.UK service for checking gaps and paying voluntary contributions is expected from spring 2027.
- Wait for your letter, then follow its instructions. It is expected to direct you to the Department for Work and Pensions, which can confirm what any gaps have done and whether paying would lift your pension. Which service you need depends on your age: the Future Pension Centre below State Pension age, the Pension Service at or above it.
- Confirm the sums before paying anything. Filling a gap may not increase a State Pension at all, and if you already have or are on course for 35 qualifying years, voluntary contributions could be money wasted.
- Allow time after paying. Contributions take up to eight weeks to show on your National Insurance record and personal tax account, according to GOV.UK.
- Be alert to scams. Letters about this arrive by post. HMRC does not ask for bank or card details by text or email, and a genuine message points you to log in at GOV.UK rather than collecting details through a link.
- Use the free help. Only DWP can tell you what a gap has done to your own State Pension. For tax problems on a low income, the charity TaxAid advises on Self Assessment and tax debt, and LITRG publishes free guidance. No claims firm is needed.
Sole traders and CIS subcontractors are squarely in the affected group. If you want the wider picture — the different classes, the thresholds, and what each one counts towards — our National Insurance guides set it out.
Written by:
Tax Rebate Services Editorial Team
Reviewed by:
Tony Shanks
,
qualified Taxation Technician (ATT)
Last updated:
This article provides general information and is correct as at the date shown. It isn't personalised tax advice — for help with your own circumstances, speak to a qualified adviser or HMRC.
