How to Reactivate My UTR Number in the UK

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If your Self Assessment record has been closed by HMRC, you usually do not need a new UTR number. In most cases, your original Unique Taxpayer Reference (UTR) stays with you for life, but your Self Assessment account may become inactive if HMRC decides you no longer need to file tax returns. If you become self-employed again, start receiving rental income, or have another reason to complete a tax return, you normally need to ask HMRC to reopen your Self Assessment record using your existing UTR.

If you are returning to self-employment, it is important to get your Self Assessment record reactivated before the filing deadline. This helps avoid delays when submitting your tax return and ensures HMRC knows about your current circumstances. If you are unsure whether your record is active, an accountant can check your status and advise on the quickest way forward. You may also find our guide on when to register for Self Assessment helpful.

How to reactivate my UTR number?

If HMRC has closed your Self Assessment record, you cannot usually reactivate the UTR itself because the number does not expire. Instead, you need to reactivate your Self Assessment account linked to that UTR.

The easiest way is to contact HMRC and tell them that your circumstances have changed. For example, you may have started trading again as a sole trader, become a subcontractor under the Construction Industry Scheme (CIS), started receiving taxable rental income, or now have another reason to submit a Self Assessment tax return.

In some cases, HMRC may ask you to complete a registration form, such as a CWF1 if you are becoming self-employed again. However, where you already have a UTR, HMRC will usually reopen your existing record rather than issue a brand-new UTR. Once the record has been reactivated, you can continue using the same UTR on future tax returns.

If you are starting a business again after a break, you may also want to read our guide on how to register as self-employed for the first time, as many of the same registration rules still apply.

How to reactivate UTR number online?

There is no dedicated online button that says “reactivate UTR number.”

Instead, if you already have a Government Gateway account, you can use the official Register for Self Assessment service to tell HMRC about your current circumstances. If you have become self-employed again or now need to complete a Self Assessment tax return, HMRC will normally use your existing UTR and, where appropriate, reopen your Self Assessment record rather than issue a new UTR.

If your previous Self Assessment record was closed, HMRC may automatically reconnect it to your original UTR after processing your registration. In most cases, the UTR itself does not change, even if you have not filed a tax return for several years.

If the online service cannot recognise your details or tells you that you already have a UTR, you may need to contact HMRC directly to ask them to reopen your Self Assessment record. This is quite common where someone stopped filing tax returns because HMRC removed them from Self Assessment, but has since returned to self-employment or now has another reason to submit tax returns.

After your record has been reopened, you can continue filing your Self Assessment tax returns using the same UTR number. If you are wondering when returns can be submitted each year, our article on when can I file my 25/26 Self Assessment explains the timetable.

Can your UTR number be deactivated?

A UTR number itself is generally not deactivated. It is a permanent reference issued by HMRC and usually stays with you for life.

What can be closed is your Self Assessment record. For example, if HMRC reviews your circumstances and decides you no longer need to complete tax returns because all your income is taxed through PAYE, they may remove you from Self Assessment. This does not mean your UTR has disappeared. It simply means that HMRC is no longer expecting you to file annual Self Assessment tax returns.

If your circumstances change later, such as becoming self-employed again, starting a property business, or receiving other untaxed income, HMRC can reopen your Self Assessment record and your original UTR will normally be used again.

For most people, there is no need to apply for a new UTR unless HMRC confirms that one has never been issued. Using your existing UTR helps keep your tax history together and avoids unnecessary delays when dealing with HMRC.

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