An agent whose client case is stuck or mishandled should work up a fixed ladder: chase through the Agent Dedicated Line or webchat once the expected reply date has passed, then use the Agent Account Manager service, and only then make a formal complaint, which can go to a second tier review, the Adjudicator’s Office and finally the Parliamentary and Health Service Ombudsman. Disputes about the tax itself or a penalty follow a different route: appeal, statutory review, alternative dispute resolution or the tribunal.

Which route fits the problem you have?

The first job is to sort the problem into one of two kinds, because HMRC treats them differently and using the wrong route costs time. HMRC’s complaints guidance says a complaint is only for unhappiness with the service received, giving delays in processing, poor communication or behaviour, and mistakes in handling a case as examples. Where the client disagrees with a decision, such as a bill, a penalty or a decision about a relief, the right step is an appeal or a review, and HMRC warns that a complaint made where an appeal or review was needed will take longer to resolve.

Service problems then run through an escalation ladder:

  1. The normal channels: the Agent Dedicated Line, webchat or post.
  2. The Agent Account Manager service, for issues normal contact has not resolved.
  3. A formal complaint, reviewed first at tier one and then, if the outcome is not accepted, at tier two.
  4. The Adjudicator’s Office, which is independent of HMRC.
  5. The Parliamentary and Health Service Ombudsman, through a referral from the client’s MP.

When should you chase through the normal agent channels?

Agents formally authorised for a client can call the Agent Dedicated Line for Self Assessment or PAYE for individuals on 0300 200 3311, Monday to Friday, 8am to 6pm. Webchat covers PAYE queries, Self Assessment registration or reactivation, cancelling a Self Assessment registration and Making Tax Digital for Income Tax. HMRC asks agents not to use either channel to chase progress before the date a reply is due, or to ask for tax or employment history that the agent can already see online.

That makes HMRC’s “check when you can expect a reply” tool the starting point for any escalation. It is updated weekly and covers areas including Self Assessment, PAYE, VAT, Corporation Tax and the Construction Industry Scheme. Record the date the query was sent and the date the tool gives, because every later step depends on showing that the reply is overdue.

Authority comes first. The dedicated lines and the escalation routes below are open only to an agent who is authorised for the client and the tax concerned, so check the authorisation is in place before chasing; see the agent services account and authorising an agent.

What is the Agent Account Manager service and when can you use it?

Agent Account Managers help agents resolve ongoing issues with HMRC that normal communications have not resolved, including Self Assessment, PAYE, VAT, Corporation Tax and repayments. Before raising an issue the agent must:

  • be authorised to represent the client in the matter in question;
  • check when a reply was expected and wait at least 20 working days beyond that date; and
  • have contacted HMRC at least twice to try to resolve it.

The service has limits. Agent Account Managers cannot give technical advice or interpret legislation, and they will not take an issue that is already the subject of a formal complaint, is part of an ongoing compliance check, or relates to an appeal against an HMRC decision.

The process changed on 1 April 2026. Agents no longer need to register with the service before raising an issue, and HMRC said it would destroy the data held for existing registrations. Each issue needs its own online form. The team acknowledges by email within 2 working days with a reference number, gives progress updates every 5 working days, and will usually resolve the issue within 20 working days or provide an action plan if it cannot.

Because the service will not look at an issue once a complaint has been made, the order of steps is important. If the problem is a delay or a lost repayment rather than a grievance about how the client was treated, the Agent Account Manager route is normally worth exhausting first.

When is a formal complaint the right step?

A complaint is the right tool when the service itself has failed: repeated delay, wrong information, a mishandled case or poor behaviour. Agents can complain online on a client’s behalf, but HMRC’s guidance says the agent must have the client’s permission to do so. Complaints can also be made by phone or post, giving the client’s identifiers, what happened and when, and how the client would like it resolved.

HMRC first carries out a tier one review, investigating what happened and what should have happened. If the outcome is not accepted, a tier two review is carried out by a different person, who also looks at how the first review was handled. The tier two decision is HMRC’s final word; there is no third internal review.

HMRC says it will consider refunding reasonable costs directly caused by its mistakes or delays, and lists postage, phone charges and professional fees as examples. Where a practice has spent hours putting right an HMRC error, the time records and invoices support that request, so keep them. Who bears the cost of the practice’s time otherwise is a separate question, covered in who pays an accountant’s fees in an HMRC enquiry.

The standards HMRC is measured against in a complaint come from its Charter; see the HMRC Charter and your rights.

What can the Adjudicator’s Office and the Ombudsman do?

The Adjudicator’s Office can investigate only after both HMRC review tiers have been completed, and only at the request of the person affected or an authorised representative. It can normally accept a complaint up to 6 months after the second tier review; later complaints may be accepted in exceptional circumstances if the reasons are explained.

It can look at whether policy and guidance were applied fairly and consistently, administrative errors including unreasonable delays, mistakes and poor or misleading advice, how discretion was used, and staff conduct that led to poor service. It cannot look at government or departmental policy, questions that a court or tribunal has a specific right to decide, ongoing investigations or enquiries, formal decisions reached through alternative dispute resolution, or complaints already investigated by the Parliamentary Ombudsman.

If the Adjudicator’s outcome is still not accepted, the client can ask their MP to refer the complaint to the Parliamentary and Health Service Ombudsman. HMRC cannot investigate a complaint while the Adjudicator or the Ombudsman is investigating it.

What if the problem is a decision rather than the service?

Where HMRC has made an appealable decision in a compliance check, its guidance says the client will usually have three options within 30 days: send new information to the officer and ask for it to be considered, have the case reviewed by a different officer, or appeal to the independent tribunal. Alternative dispute resolution can be used once a decision is made and also during a check if the client disagrees with what is being checked, without affecting the right of appeal. These routes are covered in statutory review and the tax tribunal and alternative dispute resolution.

A single case can need both routes. A delayed enquiry can justify a service complaint about the delay while the technical disagreement goes to review or appeal. Keep the two in separate correspondence so neither is treated as the other, and remember that the Agent Account Manager service will not take an issue that forms part of an ongoing compliance check.

How might an escalation look in practice?

Illustration only. A client’s Self Assessment repayment of £1,200 has not arrived. The “when to expect a reply” tool gives a date that passed several weeks ago. The agent calls the Agent Dedicated Line twice, noting the dates, names and outcomes, and is told on each occasion that the repayment is being checked. Twenty working days after the expected reply date, the agent completes the Agent Account Manager form for that single issue. An acknowledgement and reference number arrive within 2 working days and updates follow every 5 working days. If the repayment were still unresolved after the 20 working day target and the action plan were not followed, the agent, with the client’s permission, would then make a formal complaint, attaching the call log and any extra professional fees incurred.

What mistakes slow an escalation down?

  • Chasing before the expected reply date has passed, which HMRC asks agents not to do.
  • Making a complaint about a penalty or assessment that should have been appealed, so the appeal deadline passes while the complaint is handled.
  • Complaining before trying the Agent Account Manager service, which then cannot help because a complaint exists.
  • Raising several issues on one Agent Account Manager form instead of one form per issue.
  • Escalating without current authority for the client and the tax concerned.
  • Keeping no record of call dates, names and reference numbers, which leaves nothing to show the tier one reviewer or the Adjudicator.
  • Missing the 6 month window for the Adjudicator’s Office after the tier two response.

Solar Protect runs fee protection schemes for accountancy and bookkeeping practices. See how our accountant schemes work or read fee protection schemes for accountants.

Sources

Reviewed by Christine Anderson, Broker, Solar Protect. Last reviewed 8 October 2026. Part of Accountapedia, the Solar Protect guide to UK tax and accounting. This page is general information, not personalised advice.