New HMRC Tax Adviser Registration Rules for SDLT: What London Landlords Must Know

What Has Changed?

HMRC recently confirmed that from May 2026, any business or individual paid to interact with HMRC on tax matters—including Stamp Duty Land Tax (SDLT) submissions—must register as a tax adviser via the Agent Services Account. This includes conveyancers, property professionals, and firms processing SDLT returns for clients.

Previously, SDLT submission was treated largely as an administrative task. Now, it is classified as regulated tax advice, which means those involved must meet HMRC’s tax adviser standards, comply with oversight requirements, and maintain formal registration.

Why This Matters to London Landlords

For landlords, particularly those working with conveyancers or agents to handle SDLT on property purchases or transfers, this development signals a significant compliance shift. The obligation primarily lies with the service providers, but landlords should be aware of the risks:

• Compliance risk: Using unregistered advisers for SDLT matters after May 2026 could expose landlords to delays, penalties, or invalid submissions.
• Operational risk: Landlords managing property acquisitions or portfolio growth might face disruptions if their advisers are not registered.
• Financial risk: Non-compliance could result in financial penalties or additional scrutiny on SDLT filings.

Who Is Affected?

• Single-unit landlords engaging solicitors or agents to submit SDLT returns must verify those providers’ registration status.
• Portfolio landlords and property investment firms should review their entire chain of advisers submitting SDLT returns.
• HMO operators and accidental landlords using property managers or conveyancers need to ensure these professionals comply with the new rules.

Practical Steps for Landlords and Property Teams

1. Audit your SDLT advisers: Identify all professionals and firms handling SDLT submissions on your behalf.
2. Confirm registration status: From now through the May 2026 deadline, check if they are registered tax advisers via HMRC’s Agent Services Account portal.
3. Assess contractual arrangements: Include clauses requiring tax adviser registration and compliance with HMRC standards.
4. Plan contingencies: Have alternative advisers ready should your current providers fail to register.
5. Train your internal teams: For landlords with in-house property or legal teams submitting SDLT, ensure these staff understand and comply with the new registration and regulatory requirements.

For Property Professionals and Conveyancers

Firms submitting SDLT returns must:

• Register as tax advisers through HMRC’s Agent Services Account by May 2026.
• Review and update compliance frameworks to align with tax adviser standards.
• Train staff on obligations and maintain appropriate oversight.
• Document all SDLT dealings comprehensively to meet HMRC’s scrutiny.

Benchmarking and Compliance Frameworks

HMRC’s guidelines on tax adviser standards require robust governance and documentation. While exact penalties or enforcement measures may evolve, the classification of SDLT as regulated tax advice signals rigorous HMRC compliance expectations.

Landlords and their advisers should benchmark policies against professional bodies such as the Chartered Institute of Taxation (CIOT) or the Association of Taxation Technicians (ATT) and seek legal or compliance consultancy if unsure.

Timeline and Deadlines

• Immediate action: Begin identifying advisers and reviewing agreements now.
• Ongoing: Monitor registration status and compliance updates from HMRC.
• Deadline: Ensure all advisers involved in SDLT matters register by May 2026.

How Rentals & Sales Can Support You

Navigating this regulatory change requires a strategic approach. Our expert teams offer:

• Portfolio reviews to map your SDLT-related advisers and processes.
• Compliance audits to identify gaps and risks in your SDLT handling.
• Pricing strategy advice factoring in potential compliance costs.
• Liaison with property professionals to confirm adviser credentials.

Contact us to schedule a consultation tailored to your landlord profile—whether you manage a single property or a multi-unit portfolio.

Compliance Disclaimer: This article provides general guidance based on current HMRC announcements and should not be construed as legal or tax advice. Landlords and property professionals should consult qualified advisors for specific circumstances.