HMRC Speeds Up Self Assessment Registration

HMRC turned on an improved online Self Assessment registration service on 9 September, according to HMRC's own announcement. The form is now pre-filled with details HMRC already holds, lets you save it and come back, and confirms by email or text the moment it is submitted. The part that actually matters: your Unique Taxpayer Reference now lands in your online account within 72 hours, rather than the up to 15 days it used to take by post.

That gap mattered because nothing else can start until the UTR arrives. Anyone who began trading, started a side income, or first needs to file for the 2025 to 2026 tax year has to register by 5 October 2026, and the return itself is not due until 31 January 2027. A reference that used to take a fortnight to turn up by post ate into that window before you could even open the return. Getting it within three days closes most of that gap.

The faster route only applies if you are registering yourself through a Personal Tax Account. An accountant registering a client still uses the older paper-based forms, CWF1 for the newly self-employed or SA1 for anyone else, so the change lands mainly on the trader or side business owner doing it themselves rather than through an agent.

HMRC says more than 640,000 people registered for Self Assessment in the year to 31 March 2026, and by its own account most leave it until the run-up to January. If you started a side business or your first year of trading this tax year and have not registered yet, doing it now rather than in December is the one thing this change actually makes easier: register online, get the reference the same week, and the January deadline stops being a scramble.

Registering is the paperwork side of starting up. The legal requirements a website itself has to meet are a separate list, cookie notices, company details, distance-selling rules, and worth checking at the same time if the business is new. Our guides cover both once the tax return part is out of the way.