SDLT Tax Adviser Registration 2026: Everything Conveyancers Need to Know

Introduction

From 18 May 2026, every firm that submits Stamp Duty Land Tax (SDLT) returns to HMRC on behalf of clients must be registered as a tax adviser under the new HMRC Agent Services framework.

This is not optional. If your firm files SDLT returns — whether you are a conveyancing solicitor, a licensed conveyancer, or a tax agent — you must complete the registration process before the deadline or risk losing your ability to file.

This guide sets out everything you need to know: who is affected, what the prerequisites are, how to register step by step, and what happens if you miss the deadline. We have written it specifically for conveyancing professionals, cutting through HMRC's often opaque guidance to give you a clear, actionable plan.

Short on time? Use our free Tax Adviser Registration Checker to find out whether your firm is ready to register — and get a personalised action plan in under two minutes.

What Is the Tax Adviser Registration Requirement?

Background

HMRC has been modernising its agent services infrastructure for several years. The legacy Government Gateway system — which most conveyancing firms currently use to submit SDLT returns — is being replaced by the newer Agent Services Account (ASA) framework.

As part of this transition, HMRC is introducing a formal registration requirement for anyone who acts as a tax adviser. The requirement applies to all agents who submit tax returns or claims on behalf of clients, including SDLT returns.

What Changed

Previously, a firm could submit SDLT returns simply by having a Government Gateway account and the appropriate enrolment. Under the new regime, firms must additionally:

1. Create an Agent Services Account (if they have not already done so)
2. Register as a tax adviser through the ASA portal
3. Pass a series of eligibility checks including anti-money laundering (AML) supervision verification, sanctions screening, and confirmation of no outstanding tax liabilities

The registration window opened in late 2025, and the hard deadline is 18 May 2026.

Legislative Basis

The requirement stems from HMRC's powers under the Commissioners for Revenue and Customs Act 2005 and the Money Laundering, Terrorist Financing and Transfer of Funds (Information on the Payer) Regulations 2017 (as amended). It is part of a broader effort to ensure that all tax agents operating in the UK are properly supervised and accountable.

Who Needs to Register?

You Must Register If:

• You are a conveyancing solicitor whose firm submits SDLT returns on behalf of clients
• You are a licensed conveyancer filing SDLT returns
• You are a tax agent or accountant who handles SDLT as part of a broader tax practice
• Your firm uses SDLT filing software (such as StampSorted, SDLT Hub, or similar) to submit returns electronically to HMRC
• You file even one SDLT return per year on behalf of a client — there is no volume threshold

You Do Not Need to Register If:

• You are an individual taxpayer filing your own SDLT return (e.g., for a personal property purchase)
• You are a firm that only advises on SDLT but does not actually submit the return to HMRC — i.e., you calculate the liability and prepare the form, but the client or another agent submits it
• You have already ceased trading and will not submit any SDLT returns after 18 May 2026

Common Scenario: Small Conveyancing Firms

If you run a small conveyancing practice — say, one to five fee earners — and you file SDLT returns as part of your post-completion process, you must register. This applies regardless of whether you file using HMRC's online portal, approved third-party software, or paper returns.

The fact that SDLT filing is only one part of your broader conveyancing work does not exempt you. If you submit returns to HMRC on behalf of clients, you are acting as a tax adviser for the purposes of this requirement.

The Deadline: 18 May 2026

Why This Date Matters

HMRC has confirmed that 18 May 2026 is a hard deadline. After this date:

• Firms that have not registered will be unable to submit SDLT returns through HMRC's systems
• There is no grace period or transitional arrangement
• Client transactions could be delayed if your firm cannot file the SDLT return

Timeline Context

Do Not Leave It to the Last Minute

Registration is not instantaneous. Several of the prerequisite steps — particularly obtaining or verifying AML supervision details — can take days or weeks. HMRC's own systems can experience delays during peak periods.

We strongly recommend starting the process no later than April 2026, and ideally completing it by mid-April to allow buffer time for any issues.

Prerequisites: What You Need Before You Start

Before you can register as a tax adviser, you must have several things in place. Missing any one of these will block your registration.

1. An Agent Services Account (ASA)

If your firm does not already have an Agent Services Account, you must create one first. This is HMRC's modern agent portal, separate from the older Government Gateway.

To create an ASA, you need:

• Your firm's Government Gateway user ID and password
• Your firm's Unique Taxpayer Reference (UTR) or company registration number
• The name and details of the person creating the account (who must be authorised to act on behalf of the firm)

Creating an ASA typically takes 10-15 minutes if you have all the details to hand. HMRC may send a verification code by post, which can add 7-10 working days.

2. Anti-Money Laundering (AML) Supervision

Your firm must be supervised for AML compliance by a recognised supervisory body. For conveyancing solicitors in England and Wales, this is typically the Solicitors Regulation Authority (SRA). For licensed conveyancers, it is the Council for Licensed Conveyancers (CLC).

You will need to provide:

• The name of your AML supervisory body
• Your firm's AML registration number or reference
• Confirmation that your AML supervision is current and in good standing

If your AML supervision has lapsed or is under review, you cannot complete tax adviser registration until it is resolved.

3. No Outstanding Tax Liabilities

HMRC will check whether your firm has any outstanding tax debts. If you have unpaid Corporation Tax, PAYE, VAT, or other tax liabilities, this may prevent or delay your registration.

Action: Check your firm's tax position before starting registration. If you have outstanding liabilities, contact HMRC to agree a time-to-pay arrangement or settle the debt.

4. Sanctions and Fit-and-Proper Person Check

HMRC performs a background check against sanctions lists and may review whether the principals of the firm meet "fit and proper person" criteria. This is largely automated but can flag issues if:

• Any partner or director of the firm appears on a sanctions list
• The firm has been subject to regulatory action by the SRA, CLC, or another body
• There is a history of serious non-compliance with tax obligations

5. Authorised Signatory

You need an authorised person within the firm to complete the registration. This is usually a partner, director, or COFA (Compliance Officer for Finance and Administration). The person must have the authority to bind the firm.

Step-by-Step Registration Process

Step 1: Check Your Readiness

Before logging in to HMRC's portal, verify that you have all prerequisites in place. Our free Tax Adviser Registration Checker walks you through each requirement and identifies any gaps.

Step 2: Sign In to Your Agent Services Account

Go to HMRC's Agent Services Account portal and sign in with your Government Gateway credentials. If you do not have an ASA, you will be guided through the creation process.

URL: Your starting point is the HMRC agent services page on GOV.UK. Search for "HMRC agent services account" or navigate to the agent services section of your Government Gateway dashboard.

Step 3: Navigate to Tax Adviser Registration

Once signed in to your ASA, look for the "Register as a tax adviser" option. This may be listed under "Manage your account" or "Agent services" depending on the current portal layout.

Step 4: Provide Firm Details

You will be asked to confirm or provide:

• Firm name and registered address
• Firm type (solicitors' practice, licensed conveyancer, etc.)
• Company registration number or partnership UTR
• Contact details (email and telephone)

Step 5: Confirm AML Supervision

Enter your AML supervisory body and registration details. HMRC will verify this against the supervisory body's records — this verification may not be instantaneous.

Step 6: Declare Tax Compliance

You will be asked to confirm that your firm does not have outstanding tax liabilities. HMRC may cross-reference this against your tax records.

Step 7: Agree to the Terms

Read and accept the terms and conditions of registration as a tax adviser. These cover your obligations around data protection, client authorisation, and ongoing compliance.

Step 8: Submit and Await Confirmation

Submit your registration application. HMRC will process it and send a confirmation to the email address on your ASA. Processing times vary but typically take 5-10 working days.

If HMRC requires additional information, they will contact you. Respond promptly to avoid delays.

Step 9: Verify Your Registration

Once approved, log back in to your ASA and verify that your tax adviser registration status shows as active. You should also check that your SDLT filing enrolment is linked to your new registration.

What Happens If You Do Not Register?

The consequences of failing to register by 18 May 2026 are significant and immediate.

Loss of Filing Ability

Your firm will be unable to submit SDLT returns to HMRC. This means:

• You cannot complete post-completion on any property transaction that requires an SDLT filing
• Clients will not receive their SDLT5 certificate
• Land Registry applications that require an SDLT5 certificate will be held up
• The entire conveyancing chain downstream of your transaction could be affected

Client Impact

Your clients face real harm if you cannot file:

• Late filing penalties: SDLT returns must be filed within 14 days of completion. If your firm cannot file because it is not registered, the client may incur penalties of up to £1,600 or more depending on the delay
• Interest charges: Interest accrues on unpaid SDLT from the filing date
• Delayed registration at Land Registry: Without the SDLT5, the buyer cannot register their title, leaving them exposed

Professional Conduct Implications

For solicitors regulated by the SRA, an inability to complete post-completion obligations could engage the SRA's Principles and Code of Conduct — particularly:

• Principle 7: Acting in the best interests of each client
• Principle 3: Not allowing your independence to be compromised

Failing to register when you knew (or ought to have known) about the requirement could be viewed as a failure to maintain competence.

No Retrospective Filing

HMRC has not indicated that there will be any mechanism for unregistered firms to file returns retrospectively. If you miss the deadline and subsequently register, you will only be able to file from the date your registration is confirmed — not backdate filings.

Action Plan: Your Registration Timeline

If You Are Reading This Before April 2026

You have time, but do not be complacent. Here is your action plan:

This week:

1. Check whether your firm has an Agent Services Account — if not, create one immediately
2. Verify your AML supervision status with your supervisory body (SRA, CLC, etc.)
3. Check your firm's tax compliance position — are there any outstanding liabilities?

Within two weeks: 4. Use our Tax Adviser Registration Checker to identify any gaps 5. Resolve any blockers (outstanding tax debts, lapsed AML supervision, etc.) 6. Designate an authorised person within the firm to complete the registration

Within four weeks: 7. Complete the tax adviser registration through your ASA 8. Monitor your email for HMRC's confirmation 9. Once confirmed, verify your SDLT filing capability

If You Are Reading This in May 2026

Act immediately. You have days, not weeks. Prioritise:

1. If you do not have an ASA, create one today
2. Complete the registration form the same day
3. If HMRC requires verification by post, contact them by telephone to request expedited processing
4. Have a contingency plan: identify another registered firm or agent who can submit returns on your behalf if your registration is not processed in time

Practical Implications for Your Firm

Updating Your Internal Processes

Tax adviser registration is not simply an administrative box-ticking exercise. It should prompt a review of how your firm handles SDLT filing more broadly.

Consider the following:

• Who in your firm is responsible for SDLT filing? Ensure they are aware of the registration requirement and involved in the process.
• What software do you use? Confirm that your SDLT filing software is compatible with the new Agent Services Account framework. If you are using outdated tools or manual processes, now is a good time to modernise.
• Do you have a backup filing process? If your primary filer is absent (illness, leave, departure), can another team member submit SDLT returns? Under the new system, the firm's registration covers all authorised users, but you need to ensure the right people have access.
• Are your client engagement letters up to date? Some firms may wish to update their terms of engagement to reference the tax adviser registration, particularly if it affects the scope of services offered.

Training and Awareness

Ensure that all fee earners and support staff involved in post-completion understand the change. The key message is straightforward: from 18 May 2026, the firm must be registered as a tax adviser to file SDLT returns. If the registration lapses or is revoked, the firm cannot file.

Consider a brief internal briefing or training session to cover:

• What tax adviser registration means
• How it affects daily workflow (answer: it should not, once registration is complete)
• What to do if a filing fails or an error message references registration status

Professional Indemnity Insurance

While tax adviser registration itself is unlikely to affect your professional indemnity (PI) insurance premiums, an inability to file SDLT returns due to failed registration could give rise to claims. If a client suffers loss because you could not file their SDLT return on time — resulting in penalties or delayed Land Registry registration — that is a potential PI claim.

Inform your PI insurer or broker about the registration requirement, and ensure your risk management procedures account for it.

Firm Mergers and Changes of Structure

If your firm is planning a merger, acquisition, or change of legal structure (e.g., converting from a partnership to a limited company), be aware that the tax adviser registration is linked to the legal entity. A change of entity may require a new registration. Plan accordingly and build registration into your merger or conversion timeline.

Impact on SDLT Filing Software

If you use third-party SDLT filing software, the tax adviser registration does not replace your software's connection to HMRC. Rather, your software will need to be linked to a registered tax adviser account.

Most approved SDLT software providers are updating their systems to work with the new Agent Services Account framework. Check with your software provider to ensure compatibility.

If you are evaluating SDLT filing software, StampSorted is built from the ground up to work with the new ASA framework and tax adviser registration requirements. Learn more about our SDLT filing tools.

Frequently Asked Questions

1. Does every fee earner in my firm need to register individually?

No. The registration is at the firm level, not the individual level. One registration covers all fee earners within the firm who submit SDLT returns. However, the person who completes the registration must be authorised to act on behalf of the firm.

2. We use a third-party agent to file our SDLT returns. Do we still need to register?

If a separate agent (such as an outsourced post-completion provider) files your SDLT returns, that agent needs to be registered — not your firm (unless you also file returns directly). Confirm with your agent that they are registered or in the process of registering.

3. What if our AML supervision is with HMRC rather than the SRA or CLC?

Some firms, particularly standalone tax agents, are supervised for AML directly by HMRC. This is acceptable — you will need your HMRC AML supervision reference number. The process is the same.

4. Can we register if we have a time-to-pay arrangement for outstanding tax?

Generally, yes. A formal time-to-pay arrangement agreed with HMRC should not block your registration, provided you are up to date with payments under the arrangement. However, if you are in default on a time-to-pay arrangement, this may cause issues.

5. Is there a fee for registering as a tax adviser?

No. HMRC does not charge a fee for tax adviser registration. The process is free.

6. What if we only file a handful of SDLT returns each year?

The volume of returns you file is irrelevant. If you file any SDLT returns on behalf of clients, you must register. There is no minimum threshold.

7. Does this affect Scotland or Wales?

No. SDLT applies only to property transactions in England and Northern Ireland. Scotland has Land and Buildings Transaction Tax (LBTT), and Wales has Land Transaction Tax (LTT). These are administered by Revenue Scotland and the Welsh Revenue Authority respectively, and have their own agent registration requirements.

However, if your firm handles transactions in multiple jurisdictions, you should check the requirements for each.

8. What if our registration is not processed by 18 May 2026?

If you have submitted your registration application before the deadline but HMRC has not yet processed it, contact HMRC directly. They have indicated that applications submitted before the deadline will be honoured, but you should keep evidence of your submission date and follow up proactively.

9. Can we file paper SDLT returns without registering?

HMRC has indicated that the registration requirement applies to all submission methods, including paper returns. While the enforcement mechanism for paper returns is less clear than for electronic filing, you should not rely on paper filing as a workaround.

10. What ongoing obligations come with tax adviser registration?

Once registered, you must:

• Maintain your AML supervision
• Keep your firm details up to date on your Agent Services Account
• Comply with HMRC's terms and conditions for registered tax advisers
• Notify HMRC of any material changes to your firm (e.g., change of status, new partners/directors)

Key Takeaways

1. The deadline is 18 May 2026 — there is no grace period
2. All firms that file SDLT returns on behalf of clients must register, regardless of volume
3. Start now — prerequisite checks (ASA, AML, tax compliance) take time
4. Missing the deadline means you cannot file SDLT returns, which disrupts the entire post-completion process for your clients
5. Registration is free and done through your Agent Services Account

Check Your Readiness Now

Use our free Tax Adviser Registration Checker to assess your firm's readiness in under two minutes. The tool walks you through each prerequisite, identifies blockers, and generates a personalised action plan.

You can also use our SDLT Calculator to calculate stamp duty for any transaction — residential, commercial, first-time buyer, additional properties, and more.

Related Guides

• SDLT Rates 2026: Complete Guide — all current rates and thresholds in one place
• SDLT Penalties for Late Filing — understand the penalty regime and how to appeal
• SDLT Reliefs and Exemptions — every available relief explained

This guide was last updated on 16 March 2026 and reflects HMRC guidance current at that date. Tax adviser registration requirements may be subject to change — check GOV.UK for the latest position.