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What is a Tax Identification Number

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Last editedFeb 20244 min read

Tax identification numbers in the UK: what they are and how to obtain them

The tax authorities in many countries use tax identification numbers that enable them to track and monitor the tax accounts of the population. Although the UK has nothing that is formally identifiable as a tax identification number – or TIN UK, as it would be known – it does make use of several numbers that are allocated to members of the public and companies and perform a similar role to that played by a tax ID number in the UK.

Key Takeaways

  • The UK utilises the Unique Taxpayer Reference (UTR) to identify individuals and businesses for tax purposes.

  • A UTR is a 10-digit number issued for managing tax affairs and is essential for self-employed individuals, businesses, and partnerships, while companies require this number for Corporation Tax matters.

  • The Company Registration Number (CRN) is used for identifying limited companies.

Understanding the UK tax identification system

In the UK, the Unique Taxpayer Reference (UTR) acts as a unique identifier, enabling tax authorities to track and monitor the tax accounts of the population. This number interfaces individuals and businesses with their tax affairs, acting as their unique identifiers in the eyes of Her Majesty’s Revenue and Customs (HMRC).

The UTR (Unique Taxpayer Reference) is an important identification number used in the UK for tax-related matters because:

  • It is used to identify taxpayers and manage their tax affairs.

  • It enhances the efficiency of HMRC (Her Majesty’s Revenue and Customs) operations.

  • It helps maintain comprehensive taxpayer databases and implement effective tax policies.

The role of the Unique Taxpayer Reference (UTR)

The Unique Taxpayer Reference (UTR) is a 10-digit number. It is issued to any individual or business required to submit a tax return. The UTR, a distinctive identifier, facilitates all communications with HMRC, promoting efficient tax administration.

Self-employed individuals who operate as a sole trader, own a UK-registered company, or collaborate with a business partner particularly need the UTR. In the context of a business partnership, three distinct UTR numbers are involved: one for the partnership entity and one for each partner.

Registration process for individuals

To obtain a UTR, one must register for self-assessment with HMRC and supply the necessary personal and business information. The UTR is automatically assigned upon registration for Self Assessment, marking the beginning of your journey as a tax-paying individual in the UK.

If you lose your UTR, initiating immediate steps for its replacement is crucial. Don’t worry; a simple phone call to the Self Assessment helpline with your details, including your National Insurance number, can help retrieve your lost UTR.

How limited companies can obtain and use a UTR

HMRC assigns a Unique Taxpayer Reference (UTR) to limited companies upon their incorporation and registration for Corporation Tax. The UTR is used for Corporation Tax purposes and is required for all official communication with HMRC, facilitating effective correspondence and appropriate tax administration.

We should note that the UTR, more than just a tax identification number, plays a pivotal role in effectively managing a business’s tax obligations. It enables HMRC to track transactions linked to it, such as tax payments. 

How can I find my Unique Taxpayer Reference?

Although the UTR is crucial to your tax affairs, it is not issued as a card or an official UTR document. You can locate your UTR on any previous tax returns or correspondence from HMRC or directly request a copy from HMRC if you cannot find it. It’s essential to keep track of your UTR, as it is required to submit returns for use as a payment reference.

Under which circumstances may a tax identification number not be issued?

Companies that have been officially closed or dissolved, struck off and no longer appear on the public register of companies at Companies House, or have changed to a different form of business structure, such as a partnership, and are therefore no longer a registered company, will be unable to request a copy of their Corporation Tax UTR.

Company Registration Number (CRN)

In addition to the UTR, the UK’s tax system also utilises the Company Registration Number (CRN). The CRN is a unique 8-character identifier assigned by Companies House when a company is registered, serving to identify each limited company and verify its legal existence. Like the UTR, the CRN is employed in all official correspondence with Companies House.

When will I need to use my Company Registration Number?

The CRN is essential in a company’s operations. It is required at all these stages:

  • Filing annual accounts and confirmation statements

  • Registering for taxes

  • Updating company details with Companies House

  • Opening a business bank account

  • Providing credit

  • Displaying on all company stationery

  • Dealing with HMRC for Corporation Tax matters

How can I find my Company Registration Number?

The process to locate your CRN is uncomplicated. It can be found:

  • on the Certificate of Incorporation

  • on any official correspondence from Companies House

  • by searching the public register at Companies House.

Seeking assistance with your UK tax identification number and tax compliance

Managing tax identification numbers in the UK can be intricate and difficult to navigate. That’s where professional help, such as accountants or tax advisors, can be invaluable. They can guide you through the tax identification process, manage your ongoing tax obligations, and ensure your business complies with UK tax regulations.

Obtaining and managing your UK tax identification number

Professional services exist to assist you in acquiring and managing your UK tax identification number. From applying for a UTR to managing this number, professionals can help streamline the process and ensure that you meet all the requirements set out by HMRC.

Ensuring business tax compliance

Beyond tax identification number management, professionals can also guarantee your business’s compliance with UK tax regulations. From understanding and implementing tax laws to staying on top of HMRC tax governance, professionals can help businesses of all sizes ensure their tax affairs are in order.


Tax identification numbers such as the Unique Taxpayer Reference (UTR) and the Company Registration Number (CRN) are key to managing your tax affairs effectively.

Whether you’re a self-employed individual, a small business owner, or a limited company director, understanding these numbers and how to manage them is crucial in your dealings with the UK tax authorities. However, navigating the labyrinth of tax laws and regulations can be daunting.

GoCardless is partnered with Sleek, who recognise the challenges of managing your tax identification numbers and ensuring tax compliance. That’s why they offer a suite of services designed to make your life easier. From obtaining and managing your UK tax identification number to ensuring your business stays tax-compliant, Sleek's team of experts is here to help.

With our assistance, you can focus on what you do best - running your business.

Frequently Asked Questions

How do I find my Unique Taxpayer Reference number?

For individuals, you can go to your Personal Tax Account on HMRC, and you will find it under ‘Your details’ or ‘Self Assessment’. You can also check previous tax returns or any documents you may have received from HMRC, such as payment reminders or notices to file a return.

For companies, your UTR can be found within your HMRC account if you have set one up and added the Corporation Tax service or by reviewing previous tax returns and correspondence from HMRC.

Is the UTR the same as the VAT number in the UK?

No, UTR and VAT numbers are not the same. The VAT number indicates registration for VAT, while the UTR is separate and identifies the company to the inland revenue.

What is a Unique Taxpayer Reference (UTR)?

A Unique Taxpayer Reference (UTR) is a 10-digit number issued by HM Revenue & Customs (HMRC) to identify individual taxpayers, partnerships, and companies.

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