Congratulations, you’ve submitted your self-assessment tax return! That moment of relief when you click ‘submit’ and receive your confirmation is genuinely satisfying. However, filing your return isn’t quite the finish line. There are several important steps you should take immediately after submission to ensure everything’s in order and to make next year’s process significantly easier.

At Integra, we guide clients through the entire self-assessment journey, including what happens after you’ve filed. Many people assume their obligations end with submission, only to be caught out by payment deadlines, payment on account requirements, or poor record-keeping. Let’s ensure you’re fully prepared for what comes next.

First priority: Confirm your submission was successful

It might sound obvious, but countless people assume their return was filed successfully without actually checking. Technical glitches, incomplete sections, or payment processing issues can derail submissions at the last moment.

Check for your submission reference: HMRC provides a unique submission reference number when your return is successfully filed online. This typically appears on screen immediately after submission and is also emailed to the address registered on your Government Gateway account. Save this reference number, it’s your proof of filing.

Review your confirmation email: Within 24 hours of filing, you should receive an email from HMRC acknowledging receipt. If you don’t receive this confirmation, log back into your HMRC online account and check your submission status. Better to discover a problem immediately than to assume everything’s fine and face late filing penalties.

Print or save your tax calculation: Your tax calculation summary shows exactly what you owe, when payments are due, and how the figures break down. Save this document digitally and keep a printed copy with your financial records. You’ll refer to it multiple times over the coming months.

Check your payment status: If you’re paying tax online, confirm the payment has been processed. HMRC typically takes 3-5 working days to confirm payment receipt. Check your bank account to ensure the payment has left your account and appears on your HMRC statement.

Understanding your payment obligations

Filing your return is one thing; paying your tax bill is quite another. The payment deadlines are strict, and HMRC charges interest on late payments from the day after they’re due.

The 31st January deadline: If you filed your 2024/25 return, any tax owed for that year is due by 31st January 2026. This is also when your first payment on account for 2025/26 is due (more on this shortly).

How to pay: HMRC accepts various payment methods including bank transfer, debit card, direct debit, or through your bank’s online or telephone banking. Bank transfers can take up to three working days, so don’t leave payment until the deadline day.

Setting up a payment plan: If you can’t pay your full tax bill by the deadline, HMRC offers Time to Pay arrangements. These allow you to spread payments over up to 12 months, though interest still applies. You must be up to date with your tax returns and owe less than £30,000 to set up a payment plan online. Contact HMRC before the deadline passes, they’re generally more accommodating if you’re proactive.

Interest and penalties: Interest accrues daily on unpaid tax from 1st February. Additionally, penalties apply: 5% of the unpaid tax if still outstanding after 30 days, another 5% after six months, and a further 5% after 12 months.

Payment on account: What you need to know

The January double payment:

This catches many people unprepared. On 31st January 2026, you’ll pay your 2024/25 balance plus your first 2025/26 payment on account. If your tax bill was £8,000, you’re actually paying £12,000 on 31st January (£8,000 for 2024/25, plus £4,000 payment on account for 2025/26).

What if your income drops?

If you expect significantly lower profits in 2025/26, you can apply to reduce your payments on account. However, if you reduce them too much and your actual bill is higher, HMRC charges interest on the underpayment. Be conservative with reductions unless you’re genuinely confident income will fall substantially.

Planning ahead:

Payment on account creates significant cash flow implications. Build these payments into your financial planning now. Setting aside money monthly is far easier than finding a large lump sum in January and July.

Record retention: What to keep and for how long

Just because you’ve filed doesn’t mean you can shred everything. HMRC requires you to retain business records for specific periods, and failure to do so can cause serious problems if they decide to investigate.

The five-year rule: You must keep all records supporting your tax return for at least five years after the 31st January submission deadline. For your 2024/25 return filed in January 2026, that means keeping records until at least 31st January 2031.

What records must you keep? This includes:

• All business income records (invoices, bank statements, sales records)
• Evidence of business expenses (receipts, invoices, bills)
• Records of any other income (rental income, dividends, interest)
• Mileage logs if claiming vehicle expenses.
• Records of any assets bought or sold.
• Details of pension contributions and charitable donations.

Digital or paper? HMRC accepts both. Many businesses now photograph receipts and store them digitally in cloud accounting software. This approach is often more secure than paper records, which can be lost, damaged, or fade over time.

Why is this so important? If HMRC decides to enquire into your return, even years later, you’ll need to provide evidence supporting your figures. Without adequate records, HMRC may disallow expenses and issue assessments based on their estimates, which are rarely favourable.

Planning for next year’s return

The best time to prepare for next year’s self-assessment is immediately after filing this year’s. Creating good systems now will make the process immeasurably easier in 12 months.

Set up proper bookkeeping: If you’ve been scrambling through receipts and bank statements this year, resolve to do better. Implementing cloud accounting software like Xero, QuickBooks, or FreeAgent makes tracking income and expenses throughout the year effortless.

Schedule regular reviews: Rather than facing a year’s worth of transactions next January, review your accounts monthly or quarterly. This keeps records current and identifies issues early when they’re easier to resolve.

Create a tax savings account: Open a separate savings account and transfer a percentage of income regularly to cover your tax bill. Many self-employed people use a rough formula of 25-30% of income for higher-rate taxpayers, 20% for basic-rate taxpayers.

Mark key dates in your diary: 31st January (submission deadline and payment), 31st July (second payment on account), and 5th April (tax year-end). Setting reminders well in advance prevents last-minute panic.

Consider professional support: If this year’s self-assessment was stressful, time-consuming, or confusing, consider engaging an accountant for next year. At Integra, we handle the entire process from bookkeeping through to submission, giving you peace of mind and often saving you more in tax than our fees cost.

What to do if you’ve missed the deadline

If you’re reading this after 31st January and haven’t yet filed, don’t panic, but do act immediately.

File as soon as possible: Late filing penalties are time-based. You’ll face an automatic £100 penalty for filing even one day late, but the penalties increase substantially the longer you delay. After three months, HMRC adds daily penalties of £10 (up to £900). After six months and 12 months, further percentage-based penalties apply.

Pay what you can: Even if you can’t pay your full tax bill, pay whatever you can afford. This reduces the interest charges and demonstrates good faith to HMRC.

Contact HMRC: If you have a reasonable excuse for late filing (serious illness, bereavement, or unexpected disasters), appeal the penalty explaining your circumstances. HMRC does sometimes accept appeals, though they’re strict about what constitutes a reasonable excuse.

Seek professional help: If you’re struggling to complete your return, contact an accountant immediately. We can often file returns quickly once we have the necessary information, and our HMRC agent status means we can communicate directly with HMRC on your behalf.

Common post-filing mistakes to avoid

Assuming it’s done and forgetting about it: Your tax bill still needs paying, and next year’s return needs planning. Stay engaged with your tax affairs.

Ignoring payment on account: That second payment due in July often catches people unprepared. Budget for it now.

Deleting or discarding records prematurely: Keep everything for at least five years, no matter how confident you are about your return.

Not reviewing your calculation: Occasionally, HMRC’s systems make errors. Review your tax calculation to ensure it reflects what you submitted.

Failing to update your details: If you move house, change email address, or alter your business structure, update your HMRC records promptly to ensure you receive important correspondence.

Getting ahead for next year

The self-assessment cycle doesn’t end with submission, it’s continuous. Those who treat tax compliance as an ongoing process rather than an annual panic consistently achieve better outcomes and lower stress.

At Integra, we help businesses establish systems that make tax compliance effortless. From cloud accounting implementation to full-service bookkeeping and tax return preparation, we take the burden off your shoulders entirely.

If this year’s self-assessment process felt overwhelming, it doesn’t have to be that way. Professional support costs less than you might think and delivers value far beyond just filing your return. We provide strategic tax planning, ensure you’re claiming every available relief, and give you confidence that everything’s handled correctly.

You’ve filed this year’s return, well done. Now let’s make next year even smoother. Contact Integra today, and let’s discuss how we can support your business with accounting and tax services that actually make your life easier.

People Also Ask

Q1. How long after filing self-assessment does HMRC confirm receipt?
A1. HMRC typically sends email confirmation within 24 hours of successful online submission. You’ll receive a unique submission reference number immediately on screen. If you don’t receive confirmation within 24 hours, log into your HMRC account to check submission status and verify everything processed correctly.

Q2. What is payment on account for self-assessment?
A2. Payment on account is advance payment towards next year’s tax bill, required when your previous year’s tax exceeded £1,000. You make two payments (31st January and 31st July) each equal to 50% of last year’s bill. This means paying for two tax years on 31st January.

Q3. How long must I keep self-assessment records?
A3. HMRC requires you to keep all business records, receipts, invoices, and supporting documentation for at least five years after the 31st January submission deadline. For a 2024/25 return filed in January 2026, retain records until at least 31st January 2031. Digital records are acceptable.

Q4. Can I change my self-assessment after submitting?
A4. Yes, you can amend your return within 12 months of the 31st January filing deadline. Log into your HMRC account and select the amendment option. However, frequent amendments may trigger HMRC enquiries, so ensure your original return is accurate before submitting.

Q5. What happens if I can’t pay my self-assessment tax bill?
A5. Contact HMRC immediately to arrange a Time to Pay agreement, allowing you to spread payments over up to 12 months. You must be up to date with returns and owe less than £30,000 to set up online. Interest still applies, but you’ll avoid additional penalties.