HMRC Simple Assessment: Urgent Guide for Accountants & Your Clients (2025-26)

Understanding HMRC Simple Assessment for the 2025-26 Tax Year

HMRC is once again issuing millions of Simple Assessment letters (PA302) for the 2025-26 tax year. These letters are crucial communications for individuals who owe tax but are not typically within the Self Assessment system. For UK accountants, understanding and proactively managing these letters is vital to ensure your clients remain compliant and avoid unnecessary penalties.

Simple Assessment is HMRC's method of calculating and collecting income tax from individuals whose tax affairs are generally straightforward, but for whom tax cannot be fully collected through the Pay As You Earn (PAYE) system. This often applies to those with untaxed income that HMRC has information on, such as State Pension income or untaxed savings interest.

The letters for the 2025-26 tax year are being sent out from summer 2026 onwards, with a key payment deadline of 31 January 2027. This guide offers practical, actionable advice for accountants to assist clients with this potentially confusing HMRC communication.

Who Receives HMRC Simple Assessment Letters (PA302)?

Simple Assessment letters are primarily sent to individuals who do not file a Self Assessment tax return but have an underpayment of tax that cannot be collected through their tax code. HMRC uses data from various third-party sources, including employers, pension providers, banks, and the Department for Work and Pensions (DWP), to calculate the tax owed.

Common scenarios for receiving a PA302 letter include:

State Pensioners: Often, individuals receiving the State Pension have income above their Personal Allowance, and tax cannot be deducted at source from the pension itself.
Untaxed Savings Interest: With the introduction of the Personal Savings Allowance, many savers no longer pay tax on interest. However, if interest income exceeds this allowance, or if HMRC's data indicates a discrepancy, a Simple Assessment may be issued.
Untaxed Dividend Income: Similar to savings interest, dividends that are not taxed at source and exceed the dividend allowance can trigger a Simple Assessment.
Underpayments from PAYE: If an individual has underpaid tax through PAYE and the amount is too large (typically £3,000 or more) to be collected through a tax code adjustment, HMRC may issue a PA302.
Other Untaxed Income: This could include small amounts of rental income, income from a second job not taxed via PAYE, or benefits in kind where tax was not fully collected.

It's important to note that working-age customers began receiving letters from 30 June 2026, with pensioners starting to receive theirs from 12 August 2026. A second batch of letters, particularly relating to Bank and Building Society Interest (BBSI) data, will be sent between October and December 2026.

Verifying the Authenticity of a PA302 Letter

In an era of increasing online and postal scams, verifying the authenticity of any HMRC communication is paramount. Clients may feel anxious receiving a PA302 letter, making them vulnerable to fraudulent attempts.

Advise your clients to look for key indicators of a genuine HMRC letter:

Official Branding: Genuine letters will have clear HMRC branding and contact details.
Postal Delivery: HMRC typically sends Simple Assessment letters by post. They will generally not initiate contact about tax owed via email, text message, or phone calls.
Payment Reference: The letter will include a 14-character payment reference starting with 'X' if tax is due.
Personal Tax Account: If your client has a Personal Tax Account, the assessment should also be viewable there.

Action Item for Accountants: Instruct clients to never click on links in suspicious emails or texts claiming to be from HMRC. If in doubt, they should go directly to the official GOV.UK website or contact HMRC using the numbers provided on the GOV.UK site, not those on the letter itself. You can also help them verify by checking their Personal Tax Account if you have agent access.

Crucial Steps for Reviewing Simple Assessment Figures

Receiving a PA302 letter does not automatically mean the figures are correct. HMRC's calculations are based on the data they hold, which may sometimes be incomplete or inaccurate. It is absolutely critical for clients, with your assistance, to review the assessment carefully.

The 60-Day Review Window

If a client believes the Simple Assessment is incorrect, they must notify HMRC within 60 days of the date shown on the letter. Failing to act within this timeframe can make it harder to dispute the assessment later.

Key areas to check:

Income Sources and Amounts: Verify all listed income (State Pension, savings interest, dividends, employment income, etc.) against the client's own records. This includes bank statements, P60s, P45s, and pension statements.
Taxable Benefits: Ensure any benefits in kind or other taxable benefits have been correctly accounted for.
Allowances and Reliefs: Confirm that all applicable personal allowances and tax reliefs (e.g., Gift Aid, personal pension contributions) have been applied.
Tax Codes: If the client is employed or receives a private pension, check that the correct tax codes were used for PAYE income. Underpayments can occur if an incorrect tax code was applied.

If discrepancies are found, your client (or you on their behalf) should contact HMRC in writing, clearly stating which figures are believed to be wrong and providing the correct amounts with supporting evidence. HMRC will review the information and may issue a revised Simple Assessment.

Regulatory Context: The right to query a Simple Assessment is enshrined in the Taxes Management Act 1970, Section 31AA, which outlines the process for notifying HMRC of a belief that the assessment is incorrect.

Navigating Payments and the January 2027 Deadline

Once the Simple Assessment is confirmed as correct, or a revised assessment is received, the tax owed must be paid by the specified deadline. For most Simple Assessment letters issued before 31 October 2026 for the 2025-26 tax year, the payment deadline is 31 January 2027. If a letter is issued on or after 31 October 2026, payment is due within three months of the letter's date.

Payment Methods

HMRC offers several ways to pay a Simple Assessment tax bill:

Online: Via the GOV.UK website or the HMRC app.
Bank Transfer: Using the 14-character payment reference from the PA302 letter.
Cheque: Sent to HMRC's payment address.

Important: Advise clients to use the correct payment reference to ensure the payment is allocated correctly.

What Happens if Payment is Missed?

Failure to pay by the deadline can result in penalties and interest charges. HMRC applies an automatic £100 penalty for late filing of Self Assessment returns, and similar principles apply to unpaid Simple Assessments. Late payment interest is charged at the Bank of England base rate plus 4 percentage points.

Action Item for Accountants: If a client anticipates difficulty in paying, encourage them to contact HMRC immediately to discuss a 'Time to Pay' arrangement. This allows the client to set up an instalment plan, potentially avoiding penalties.

Proactive Strategies for Accountants: Supporting Your Clients

As trusted advisors, accountants are uniquely positioned to guide clients through the complexities of HMRC deadlines and communications. Proactive engagement around Simple Assessment can significantly reduce client stress and ensure compliance.

Client Education: Inform clients about Simple Assessment, who might receive it, and what to do. A simple email or newsletter explaining HMRC tax letters 2025-26 can be invaluable.
Proactive Outreach: Consider which of your clients might be susceptible to receiving a PA302 (e.g., pensioners, those with significant savings interest). Reach out to them offering your review services.
Data Management: Maintain robust and up-to-date client data, including income sources, allowances, and previous tax payments. This will expedite the review process if a PA302 is received.
Verification Service: Offer a service to verify the authenticity of HMRC letters and to meticulously check the figures against the client's records. This adds significant value and peace of mind.
Dispute Resolution: Be prepared to assist clients in disputing incorrect assessments within the 60-day window, gathering necessary evidence, and communicating with HMRC on their behalf.

By offering these services, you not only help clients navigate a potentially confusing process but also reinforce your role as an indispensable compliance partner, much like assisting with AML compliance or ensuring registered office obligations are met.

Leveraging Digital Tools for Simple Assessment Compliance

In today's digital landscape, accounting practices can significantly enhance their efficiency and client service by utilising appropriate software and tools to manage Simple Assessment requirements.

Practice Management Software: Use your existing practice management system to log all client communications, including the dates PA302 letters are received and the 60-day review deadlines. This helps track progress and ensures no client falls through the cracks.
Document Management Systems: Securely store client financial documents (P60s, bank statements, pension statements) digitally. This provides instant access to necessary information for verifying Simple Assessment figures. Secure client portals can also facilitate easy and safe information exchange.
Automated Reminders: Set up automated reminders for key dates, such as the 60-day review period and the 31 January 2027 payment deadline. This reduces the risk of missed deadlines and associated penalties.
Client Communication Platforms: Utilise secure messaging or portals to communicate with clients about their PA302 letters, providing clear instructions and requesting necessary information efficiently.

Digital tools are not just about automation; they are about creating a robust, auditable, and efficient workflow that supports both your practice and your clients in meeting their tax obligations with confidence.

Conclusion: Empowering Your Practice for Simple Assessment Success

The ongoing issuance of HMRC Simple Assessment letters (PA302) for the 2025-26 tax year represents a significant, yet routine, compliance challenge for many UK individuals. For accountants, this is an opportunity to demonstrate invaluable expertise and proactive client care. By understanding who is affected, how to verify authenticity, the critical 60-day review window, and the January 2027 payment deadline, you can effectively guide your clients.

Embrace a proactive approach, educate your client base, and leverage digital tools to streamline your processes. This will not only ensure your clients meet their obligations but also strengthen their trust in your practice as a comprehensive and forward-thinking financial partner. Don't let these letters become a source of anxiety; instead, transform them into a testament to your practice's commitment to compliance excellence.