A Million People Missed the Self Assessment Deadline — Are You One of Them?

The 31 January deadline has come and gone, and HMRC has confirmed that 11.48 million people filed their Self Assessment tax return on time. That sounds like a lot — and it is — but with over 12 million returns expected, it means an estimated one million people missed the cut.

If you're in that group, you're not alone. But it's important to act quickly, because the penalties for late filing don't wait around.

The last-minute rush

As always, plenty of people left it very late. Nearly 476,000 people filed on deadline day itself, with the busiest hour between 5pm and 6pm when almost 33,000 returns were submitted. More than 27,000 people filed in the final hour before midnight. HMRC even opened their helplines on a Saturday to handle the demand, fielding over 10,000 calls and more than 5,000 webchats on the day alone.

Despite all of that, a significant number of people still didn't make it. If that includes you, the most important thing you can do right now is file as soon as possible.

What happens if you've missed the deadline?

The penalties for late filing start immediately and get worse the longer you leave it.

From the moment the deadline passed, a £100 fixed penalty applies — and that's the case even if you don't owe any tax at all. It's a common misconception that if there's nothing to pay, there's nothing to worry about. That's not how it works.

After three months, HMRC starts adding daily penalties of £10 per day, up to a maximum of £900. So by the time you reach the six month mark, you could already be looking at £1,000 in penalties before tax is even considered.

At six months, a further penalty is added — either 5% of the tax you owe or £300, whichever is the higher figure. At twelve months, the same again.

On top of all of that, if you have tax to pay, late payment penalties of 5% apply at 30 days, six months and twelve months — and interest is charged on anything left outstanding throughout.

It adds up quickly. The sooner you file, the sooner you stop the clock on those daily charges.

Can't pay your tax bill in full?

If you've filed but you're worried about paying what you owe, don't ignore it. HMRC does offer Time to Pay arrangements for people who genuinely can't pay in full, which allows you to spread the cost in instalments. You'll need to meet certain criteria, but it's worth exploring rather than doing nothing and letting the interest and penalties mount up.

Making Tax Digital is almost here

While we're on the subject of Self Assessment, there's something else on the horizon that a lot of people aren't fully prepared for.

From 6 April 2026, Making Tax Digital (MTD) for Income Tax becomes mandatory for sole traders and landlords with qualifying income over £50,000. That date is closer than it feels, and for many people it represents a significant change to how they manage their tax affairs.

Under MTD, you'll need to keep digital records of your income and expenses and submit quarterly updates to HMRC throughout the year — rather than completing a single annual return. It's a different way of working, and getting the right software and processes in place takes time.

If your income is between £30,000 and £50,000, the same requirements will apply from April 2027, so it's worth getting ahead of it regardless of which group you fall into.

The businesses and landlords who will find the transition easiest are the ones who start preparing now — not the ones who leave it until the rules are already in force.

We're here to help

Whether you need to get a late tax return filed, want to understand where you stand with penalties, need help setting up for Making Tax Digital, or just want someone to talk it through with — that's exactly what we're here for.

Get in touch with the team at Alera Accounting & Advisory today. We'll take it off your plate.

Source - https://www.gov.uk/government/news/1148-million-beat-the-self-assessment-deadline