Why the 5 October Deadline is Critical
Under Section 7 of the Taxes Management Act 1970 (Notice of liability to tax), any individual who has taxable income for which tax has not been deducted at source must give notice to HM Revenue & Customs by 5 October following the end of the tax year.
For the 2025/26 tax year (which ran from 6 April 2025 to 5 April 2026), that notification deadline is 5 October 2026.
2025/26 Self Assessment Thresholds at a Glance
| Income Stream | 2025/26 Exemption Threshold | Must You Register by 5 Oct? |
|---|---|---|
| Sole Trader / Freelance | £1,000 gross trading turnover (ITTOIA 2005 s.783A) | Yes, if gross turnover exceeds £1,000 (even at a net loss). |
| Property / Airbnb Let | £1,000 property allowance (ITTOIA 2005 s.783B) | Yes, if gross rent > £1,000 or net profit is £2,500–£9,999. |
| Capital Gains (Shares/Crypto) | £3,000 net annual exempt amount | Yes, if net gains exceed £3,000. |
| High Income Child Benefit | £60,000 adjusted net income | Yes, if income > £60,000 and Child Benefit was claimed. |
| Dividends | £500 dividend allowance | Yes, if dividend income outside ISAs exceeds £500. |
| PAYE Salary > £100k / £150k | Threshold removed by HMRC in 2024/25 | NO, if taxed purely through PAYE with no other untaxed income. |
The Big Myth: Do High PAYE Earners (> £100k) Need to Register?
For years, HMRC required anyone earning over £100,000 (and later £150,000) through their employer’s PAYE system to file a Self Assessment return purely because of their salary.
The UTR Timeline: From 5 October to 31 January
Here is what the schedule looks like if you register on time versus leaving it to the last minute:
How to Register on GOV.UK Today
- Go to the official HMRC registration page at gov.uk/register-for-self-assessment.
- Sign in using your Government Gateway user ID (or create one in 2 minutes if you don't have one).
- Provide your National Insurance number, date of birth, and home address.
- Specify your business/income start date (must be between 6 April 2025 and 5 April 2026 for the 2025/26 tax year).
- Submit and save your confirmation reference. HMRC will send your UTR by post.
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