HMRC identity unknown notices

Q: How might one work in practice?

Illustration only. HMRC's risk work suggests that some UK buyers of a particular overseas investment product, sold through a UK introducer, have not reported the income it pays, but HMRC cannot tell which of the introducer's clients bought it. An authorised officer, with Senior Civil Service consent, applies without notice to the tribunal for approval of a notice requiring the introducer to list the UK clients who bought the product in a stated period, with the amounts invested. The tribunal checks the four paragraph 5(4) conditions, including whether HMRC could get the information more easily elsewhere, and approves. The introducer receives a notice stating that it is tribunal approved. It can appeal only if producing the list would be unduly onerous, perhaps arguing for a shorter period or a simpler format. Once HMRC has the names, it can open checks into individual buyers using ordinary taxpayer notices.

An identity unknown notice is a Schedule 36 information notice that HMRC sends to a business or other person holding records about taxpayers whose names HMRC does not yet know. Only an authorised officer can give one, and in most cases the First tier Tribunal must approve it first, after being satisfied of four conditions set out in paragraph 5(4) of Schedule 36 to the Finance Act 2008.

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What is an identity unknown notice?

Paragraph 5 of Schedule 36 to the Finance Act 2008 lets an authorised officer of HMRC require a person, by notice in writing, to provide information or produce a document that is reasonably required to check the tax position of, or to collect a tax debt of:

a person whose identity is not known to the officer; or
a class of persons whose individual identities are not known to the officer.

The tax debt purpose was added by the Finance Act 2021. The recipient is a third party, typically a bank, platform, agent or other business that holds records about its customers. The difference from an ordinary third party information notice is that a third party notice requires HMRC to know who the taxpayer is, whereas this notice exists precisely because it does not (CH23060).

The notice sits alongside the other Schedule 36 powers. For how taxpayer notices work generally, see our guide to the Schedule 36 information notice.

What must the tribunal be satisfied of before approving one?

Paragraph 5(3) says an officer may not give the notice without the approval of the tribunal. Under paragraph 5(4), the tribunal may not approve it unless it is satisfied that:

the information or documents are reasonably required to check the tax position, or collect a tax debt, of the unknown person or class;
there are reasonable grounds for believing that the person, or any of the class, may have failed or may fail to comply with any provision of the law relating to tax, including the tax law of a territory outside the United Kingdom;
any such failure is likely to have led, or to lead, to serious prejudice to the assessment or collection of tax; and
the information or document is not readily available from another source.

HMRC’s guidance at CH24240 says “seriously prejudice” suggests a step that could have a major negative impact on the assessment or collection of tax, giving the loss of significant amounts of tax and tipping off someone suspected of a serious civil offence as examples.

The application may be made without notice (paragraph 5(3A)), so neither the recipient nor the unknown taxpayers are told about the hearing. If approval is given, the notice must say so (paragraph 6(3)), and paragraph 6(4) makes the tribunal’s approval decision final.

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Who inside HMRC can give the notice?

Only an authorised officer can give an identity unknown notice (paragraph 5(1) and CH21720). HMRC’s operational guidance at CH262500 adds internal safeguards:

the authorised officer must be a senior officer at Grade 6 level, either in one of the specialist directorates named in the guidance or nominated for the role in other business areas;
where tribunal approval is needed, the authorised officer can only apply after a member of the Senior Civil Service has consented, and consent is needed for each case separately;
the authorised officer should consider having a lawyer from HMRC Legal Group attend the hearing.

CH21720 says an authorised officer must stand back and reach a fresh view, and must be satisfied that the proposed notice is appropriate and proportionate to the risks identified.

When is tribunal approval not needed?

HMRC’s guidance at CH23920 and CH24200 lists cases where an identity unknown notice can be given without the tribunal’s approval:

a notice to a parent undertaking to check the tax position of one or more subsidiaries whose identities are not known (paragraph 35);
a notice to a partner to check the position of other partners in their capacity as such (paragraph 37);
a notice that refers only to information or documents about a pensions matter, such as a registered pension scheme (paragraph 34B);
a notice that refers only to information or documents about an electronic sales suppression tool.

Notices to “involved third parties” could also be given without approval, but only between 1 April 2010 and 31 March 2012. From 1 April 2012 HMRC obtains that kind of information under the data gathering powers in Schedule 23 to the Finance Act 2011 (CH24200); see HMRC bulk data gathering powers.

How is it different from an identification notice?

Paragraph 5A creates a narrower tool, the identification notice. It applies where HMRC does not know a taxpayer’s identity but already holds information from which someone else can work it out, such as an account reference or transaction details. The officer must have reason to believe the recipient obtained information about the taxpayer in the course of carrying on a business and can identify them, and the identity must not be readily obtainable by other means. The notice can only ask for “relevant information”: name, last known address and, for an individual, date of birth (paragraph 5A(6)).

An identification notice needs no tribunal approval. CH23080 explains that this is because these notices are designed to let HMRC respond promptly to international requests for information, and that they can be used in other circumstances only where proportionate and justified. An identity unknown notice, by contrast, can ask for any information or documents reasonably required, which is why the tribunal stands in front of it.

Can the recipient appeal?

Paragraph 31 gives the recipient a right of appeal against the notice or any requirement in it, but only on the ground that complying would be unduly onerous. The appeal must be made in writing to the officer who gave the notice within 30 days of the date it was given, stating the grounds (paragraph 32). The recipient cannot argue that the unknown taxpayers are compliant or that HMRC’s suspicions are wrong; those were for the tribunal at the approval stage. The general route is covered in appealing an information notice.

Where the notice is one of the exceptions above, such as a notice to a parent undertaking or partner, CH23940 and CH23960 say the recipient can appeal on any grounds except against a requirement to produce statutory records, unless tribunal approval was in fact obtained.

The usual Schedule 36 restrictions still apply. A notice cannot require legally privileged material, for example. However, paragraph 26(2) removes the auditor and tax adviser protections for information giving the identity or address of a person the notice relates to, or of someone who acted on that person’s behalf.

What happens if the recipient does not comply?

The standard penalties apply: £300 under paragraph 39, then up to £60 a day under paragraph 40 while the failure continues (CC/FS2). Identity unknown notices have an extra sanction. Under paragraph 49A, if daily penalties have been assessed, the failure continues for more than 30 days after the assessment was notified, and the person has been warned, HMRC can ask the tribunal for an increased daily penalty of up to £1,000 a day. In setting the amount the tribunal must consider the likely cost of complying, any benefit to the person of not complying and any benefit to anyone else (CH26710). CH26705 says this applies to failures beginning on or after 1 April 2012. The full penalty ladder is explained in penalties for not complying with an information notice.

Because the notice is tribunal approved under paragraph 5, concealing or destroying a document it requires is a criminal offence under paragraph 53; see the offence of concealing documents from HMRC.

How might one work in practice?

Illustration only. HMRC’s risk work suggests that some UK buyers of a particular overseas investment product, sold through a UK introducer, have not reported the income it pays, but HMRC cannot tell which of the introducer’s clients bought it. An authorised officer, with Senior Civil Service consent, applies without notice to the tribunal for approval of a notice requiring the introducer to list the UK clients who bought the product in a stated period, with the amounts invested. The tribunal checks the four paragraph 5(4) conditions, including whether HMRC could get the information more easily elsewhere, and approves. The introducer receives a notice stating that it is tribunal approved. It can appeal only if producing the list would be unduly onerous, perhaps arguing for a shorter period or a simpler format. Once HMRC has the names, it can open checks into individual buyers using ordinary taxpayer notices.

What should a business that receives one do?

Check whether the notice states that the tribunal approved it, because that affects the offence risk and the scope of any appeal.
Diarise the 30 day appeal window and the compliance date, and raise any genuine burden with the officer early.
Preserve every document within the notice’s description; do not apply routine deletion policies to them.
Do not tell customers about the notice unless you have considered whether doing so is appropriate; HMRC’s guidance treats tipping off as one of the harms the process is meant to avoid.
Remember that client confidentiality is not, by itself, a reason to withhold; CH26220 says there is no exemption from information powers on grounds of confidentiality.

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Reviewed by Christine Anderson, Broker, Solar Protect. Last reviewed 24 October 2026. Part of Accountapedia, the Solar Protect guide to UK tax and accounting. This page is general information, not personalised advice.