In July 2026 HMRC admitted that around 800,000 people who registered as self-employed between 2015 and 2024 may be carrying gaps in their National Insurance record, and roughly 160,000 of them are already at or within two years of state pension age (MoneySavingExpert, 2026). HMRC's advice to affected people is two words: sit tight.
That is fine advice for HMRC. It is not a financial plan, and it is not what I'd tell a client.
TL;DR: HMRC's own records were wrong for nearly a decade, and hundreds of thousands of self-employed people have state pension gaps they don't know about. "Sit tight" is HMRC's convenience, not your plan. Check your record now, because for most affected people, paying to fill the gaps pays back many times over.
What actually went wrong here?
Since 2015, telling HMRC you're self-employed has taken two separate actions, and almost nobody knows that. You register for Self Assessment, and you separately notify HMRC of self-employment on a form called the CWF1. The CWF1 is what sets you up to pay Class 2 National Insurance, the cheap contribution that buys a qualifying year towards your state pension.
Miss the CWF1 and you could file your tax returns, pay your income tax, feel completely compliant, and still never be set up to pay Class 2. So a diligent person who paid everything they were asked to pay ends up with a hole in their pension record through no fault of their own. That is the trap, and it ran for nine years before HMRC fixed the plumbing for 2024/25 onward.
So why not just sit tight?
Because "sit tight" answers HMRC's problem, not yours. HMRC doesn't want a million people jamming its phone lines or filing retrospective CWF1s and cutting across an automated fix, and for the systemic correction that's fair enough. Don't do either of those.
But the fix is slow. HMRC won't write to most affected people until spring 2027, and those nearest pension age only get their letters by summer 2027 (MoneySavingExpert, 2026). I'd rather find a five-year gap now, on my own time, than have a client discover it at 66 when the cheap window has closed. This is the same instinct I wrote about in what audit taught me: check the system, don't trust it.
Is it worth paying to fill the gaps?
For most affected people, the maths isn't close. The full new state pension is £241.30 a week in 2026/27, and you need 35 qualifying years for the full amount and at least 10 years for anything at all (GOV.UK, 2026). Each qualifying year is worth roughly £6.90 a week, about £359 a year, for the rest of your life.
A year of Class 2 costs £3.65 a week in 2026/27, roughly £190 for the year (GOV.UK, 2026). Pay about £190 once, collect roughly £359 every year you're retired. Over a normal retirement that's several thousand pounds back on a couple of hundred out.
Better still, HMRC is letting affected people backfill to 2015 at the original rates, rather than the usual six-year limit on voluntary contributions. But it isn't worth it for everyone. Someone who already has 35 qualifying years from employment gains precisely nothing. Working out who's affected and running that maths client by client is exactly what an accountant is for.
What I'm actually doing for self-employed clients
For every self-employed client, I'm checking their National Insurance record against their trading history, rather than waiting for a letter. If the CWF1 was missed, there's likely a gap, and I want it identified while the low-rate backfill window is open.
You can start yourself. Check your record and forecast at GOV.UK, and if you took on self-employment any time from 2015, treat an unbroken run of full pension years as something to verify, not assume. HMRC will fix the plumbing, but nobody there is going to work out whether it's worth you paying to fill your particular gaps. That decision is yours to make, not something to leave to a letter that might arrive in 2027. It rhymes with what I've said about HMRC's own figures being wrong at scale: the department's data is a draft to check, not an answer to accept.
Frequently Asked Questions
I registered as self-employed after 2015. Do I have gaps in my National Insurance record?
Possibly. If you registered for Self Assessment but never filed the separate CWF1 form, you may not have been set up to pay Class 2 National Insurance, which leaves gaps even though you filed and paid your tax. Check your record at GOV.UK rather than assuming it's complete.
What is the CWF1 form and why does missing it matter?
The CWF1 notifies HMRC you've become self-employed and sets you up to pay Class 2 National Insurance. Registering for Self Assessment alone did not do that between 2015 and 2024. Class 2 buys a qualifying year towards your state pension, so missing the CWF1 could quietly cost you qualifying years.
Should I pay voluntary Class 2 now or wait for HMRC to fix it?
Don't file a retrospective CWF1 or flood HMRC's phone lines, as it asks. But there's no reason not to have your record checked now. If you have gaps, HMRC is allowing backfill to 2015 at the original rates, and paying around £190 for a qualifying year worth roughly £359 a year is a strong return. Whether it's worth it depends on how many years you already have.
If you took on self-employment any time from 2015 and you're not certain your National Insurance record is clean, get in touch and I'll check it against your trading history and tell you whether filling any gaps is worth the money for your situation.