Updated for 2026. Written by Tax Dispute Consultants, specialist ex-HMRC tax investigation team. Read time: 7 minutes.

HMRC has no statutory deadline to close a Self Assessment enquiry. Some enquiries run for years. But taxpayers are not powerless: section 28A(4) TMA 1970 gives you the right to apply to the First-Tier Tribunal for a direction requiring HMRC to close the enquiry and it works.

On this page

  1. What a closure notice is
  2. The problem: no statutory deadline
  3. The taxpayer’s remedy: s28A(4) TMA 1970
  4. The FTT test
  5. Procedure: how to apply
  6. What HMRC must show
  7. The application as a lever
  8. Costs
  9. Frequently asked questions

What a closure notice is

Section 28A TMA 1970 imposes a statutory obligation on HMRC to issue a closure notice once it has completed its enquiries into a Self Assessment return. The closure notice must either state that no amendment to the return is required or specify any amendment that HMRC is making. Once issued, the closure notice ends the formal enquiry, the return is treated as having been made (or amended) as stated in the notice.

The closure notice is the mechanism by which the enquiry formally concludes. Until HMRC issues it, the enquiry remains technically open and the taxpayer lives under the continuing uncertainty and burden of an unresolved investigation.

The problem: no statutory deadline

HMRC has no fixed statutory deadline by which it must complete its enquiry and issue a closure notice. This is a significant asymmetry: HMRC has a strict 12-month window to open an enquiry (see our guide on the enquiry window), but there is no equivalent restriction on how long it can take to close one.

In straightforward cases, HMRC typically resolves an enquiry within 12 to 24 months. In complex cases, particularly those involving offshore structures, substantial business records or multi-year investigations, enquiries have been known to run for five, seven or even ten years. The burden falls disproportionately on the taxpayer, who must maintain records, fund representation and live with the uncertainty throughout.

Key point: An unreasonably prolonged enquiry is not something you have to simply endure. The law provides a direct remedy, and it is one of the most effective tools available to a taxpayer in a protracted investigation.

The taxpayer’s remedy: s28A(4) TMA 1970

Section 28A(4) TMA 1970 gives the taxpayer the right to apply to the First-Tier Tribunal (Tax Chamber) for a direction requiring HMRC to issue a closure notice within a period specified by the tribunal.

This is a statutory right, not a discretionary remedy that the tribunal may decline to consider. Once the application is made, the FTT has the power to direct HMRC to close and will do so unless HMRC can satisfy the tribunal that there are reasonable grounds for the enquiry to continue.

The equivalent provisions apply to partnership enquiries (s28B TMA 1970) and to corporation tax enquiries under Schedule 18 FA 1998.

The FTT test: “reasonable grounds”

The tribunal will direct closure unless HMRC can show reasonable grounds for not doing so , that is, unless HMRC satisfies the FTT that the continued enquiry is genuinely justified by specific investigative steps that are still in progress and whose completion is proportionate and timely.

The test is deliberately protective of taxpayers. The burden is on HMRC to justify continued investigation, not on the taxpayer to demonstrate that it is unjustified. HMRC must point to specific, concrete investigative work that remains incomplete, vague assertions that the enquiry is “ongoing” or that HMRC “may have further questions” are insufficient.

The leading authority, Jade Palace Ltd v HMRC [2006] SSCD 443, established that a mere desire to gather more information does not constitute reasonable grounds for continuing an enquiry indefinitely. HMRC must be able to identify what it has yet to investigate, why it is genuinely necessary and how long it will take.

Procedure: how to apply

Making a closure notice application is more straightforward than many taxpayers assume.

  1. No prescribed form. There is no mandatory form for a closure notice application to the FTT (Tax Chamber). The application is made in writing to the tribunal, identifying the enquiry, the taxpayer and the grounds for seeking closure.
  2. Notify HMRC. The application is served on HMRC, which is then required to respond to the tribunal setting out its grounds for opposing the direction.
  3. Decision on papers. In the majority of cases, the FTT decides the application on written submissions without an oral hearing. An oral hearing may be requested or directed if the issues are complex.
  4. Timeline. Most closure notice applications are determined within six to twelve weeks of submission, though this varies with tribunal capacity.
  5. The direction. If the FTT grants the application, it will specify a period within which HMRC must issue the closure notice. A period of 30 to 90 days from the direction is typical.

What HMRC must show to resist the direction

To resist a closure direction, HMRC must demonstrate “reasonable grounds” for the enquiry to continue. In practice, HMRC’s response to a closure notice application must identify:

  • Specific investigative steps that are incomplete (e.g., outstanding third-party information requests, pending forensic analysis of documents, awaited responses from overseas tax authorities)
  • Why those steps are proportionate to the scale of the enquiry
  • A realistic timescale for completing them

Generic assertions about the complexity of the taxpayer’s affairs or references to resource constraints within HMRC, do not constitute reasonable grounds. The FTT applies the test robustly.

Where HMRC has failed to take meaningful investigative steps for many months or where it has been asking the same questions without progressing to new ground, the case for a closure direction is strong.

The application as a lever

One of the most notable features of the closure notice application in practice is its effect on HMRC’s behaviour before the tribunal makes its decision. In a significant proportion of cases, HMRC, upon receiving notification that an application has been made, will accelerate the enquiry, take meaningful investigative steps or engage in settlement discussions in order to avoid an adverse tribunal direction.

In other words, simply making the application often achieves its intended purpose: getting HMRC to move. This makes the closure notice application one of the most cost-effective procedural tools in the tax investigation practitioner’s toolkit.

In practice: We have seen cases where HMRC settled or closed an enquiry within weeks of receiving a closure notice application, enquiries that had been drifting for two or three years. The application focuses HMRC’s attention and creates a hard deadline that it otherwise lacks.

Costs

The First-Tier Tribunal (Tax Chamber) operates predominantly as a no-costs jurisdiction in tax appeals and applications. In the absence of unreasonable conduct by either party, each side bears its own costs.

This means that making a closure notice application does not carry the risk of a costs order against the taxpayer if it fails. The cost of the application is the professional fees for preparing and lodging it, typically a fraction of the cost of continuing to fund representation in a protracted enquiry.

For the full picture of the enquiry process and how it resolves, see our pillar guide: HMRC Self-Assessment Enquiry, What Happens and What to Do.

Is your enquiry taking too long?

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Frequently asked questions

How long is too long for an HMRC enquiry?

There is no fixed statutory limit on how long an enquiry can run. However, the First-Tier Tribunal has shown willingness to direct closure where enquiries have been running for 18 months or more without genuine substantive progress. The question is not simply duration but whether HMRC’s continued investigation is justified by specific, ongoing investigative steps. An enquiry of two or more years with no clear forward movement is a strong candidate for a closure direction application.

Can I apply for a closure notice myself without a tax adviser?

Technically yes, there is no requirement to be represented before the First-Tier Tribunal (Tax Chamber). However, making an effective closure notice application requires drafting a submission that identifies the lack of reasonable grounds for HMRC’s continuing enquiry, anticipates HMRC’s justification and presents the factual timeline persuasively. In practice, professional representation substantially improves the prospects of success and is strongly advisable.

What happens if HMRC does not comply with the FTT direction?

If HMRC fails to issue the closure notice within the period specified by the FTT, the taxpayer can apply to the tribunal for enforcement. Non-compliance with a tribunal direction is a serious matter, and HMRC is virtually never in breach of a direction. In practice, compliance is essentially guaranteed, the real value of the direction is in compelling HMRC to commit to a timeline for closing the enquiry.

Will making a closure notice application damage my relationship with HMRC?

A closure notice application is a legitimate statutory right, not a hostile act. HMRC officers are aware that taxpayers have this remedy and do not treat its exercise as an aggravating factor in the enquiry. In our experience, the application frequently prompts HMRC to accelerate the enquiry or reach settlement without the need for a full hearing, it is one of the most practical tools available to a taxpayer facing an unnecessarily protracted enquiry.

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