HMRC have published their Agent Update for September 2025. We have summarised the key content with links to our detailed guidance on the topics covered, including an increase in phishing scams, changes to PAYE responsibilities involving umbrella companies, and the correct reporting of National Insurance Contributions (NICs) for internationally mobile employees.
Register clients for Self Assessment now
Tax agents should ensure any clients new to Self Assessment and who need to submit a tax return for 2024-25 have registered for Self Assessment.
- The deadline is 5 October 2025 to avoid a penalty.
Equally, if you have clients who no longer need to file a tax return, tell HMRC as soon as possible to avoid penalties for failing to submit.
'Tax help for hustles' campaign: new resources for agents and their clients
HMRC's 'Tax help for hustles' campaign helps those with side hustles get their tax right.
- The campaign is important in promoting tax compliance and supporting people who are largely unaware of their tax responsibilities.
HMRC are asking agents to share and promote its new campaign with clients who may find it useful.
- HMRC have provided a Campaign resource pack for agents to share with their clients.
2024-25 Self Assessment special cases, individuals and special exclusions trust updates
The Self Assessment special document for individuals and special exclusions for trusts has been updated, setting out whether Self Assessment taxpayers should file a paper tax return rather than an online one.
- Self Assessment technical specifications 2025 for individuals.
- Self Assessment technical specifications 2025 for trust and estate returns.
Get ready for Making Tax Digital (MTD) for Income Tax
HMRC is hosting a series of MTD for Income Tax events across the UK this year.
- Agents and software developers are welcome to attend one of these sessions to help them prepare for when MTD for Income Tax becomes a legal requirement in April 2026.
By attending one of these events, you will:
- Learn more about taking part in the testing phase and the additional support you will receive.
- Receive hands-on guidance to sign up for testing.
- Understand which of your clients will fall under MTD for Income Tax.
- Gain clarity on MTD obligations and compatible software.
- Discuss managing clients using the Agent Services Account.
- Have the opportunity to ask HMRC your MTD-related questions.
Registration is now open for the following events, which will each take place from 11am to 3pm:
- Tuesday 28 October 2025 - Leeds.
- Tuesday 11 November 2025 - Edinburgh.
- Wednesday 19 November 2025 - Belfast.
You will need to email
We also have a wide range of resources available for our members to help you prepare your practice for MTD for Income Tax, including webinars, checklists, discussion groups and Practical tax guidance.
- Explore our Making Tax Digital for Income Tax resources.
Protect your agent account from phishing scams
Criminals are using increasingly sophisticated methods to target tax agents, including phishing emails claiming to be from realistic companies, clients and HMRC.
- This is an attempt to steal personal information.
- If your device becomes infected, a criminal may have access to everything you use it for, including your agent online services account or agent services account.
HMRC will only ever email you from an email address that ends in gov.uk. The gov.uk will only feature at the end of an email address, not in the middle, for example:
- @hmrc.gov.uk
- @tax.service.gov.uk
- @advice.hmrc.gov.uk
- @updates.hmrc.gov.uk
HMRC have also provided a List of recent emails they have sent to help you decide if the email you have received is genuine.
- If you have received a phishing email that mentions HMRC, you can report it by forwarding the email to
This email address is being protected from spambots. You need JavaScript enabled to view it. - You can also Report suspicious HMRC texts, social media accounts and phone calls.
If you think you have been a victim of fraud, report it immediately to HMRC's online services team.
Guidance for labour supply chains featuring umbrella companies: PAYE responsibilities
HMRC has published Guidance on significant changes to umbrella company regulations.
- From April 2026, recruitment agencies (or, in their absence, end clients) will be accountable for Pay As You Earn (PAYE) on payments to workers supplied through umbrella companies.
- The guidance provides detailed information on the changes that have been designed to tackle non-compliance in the umbrella company market.
HMRC are putting on a webinar to help those impacted understand the implementation requirements and ensure compliance readiness. You can Register here.
Tax advice: do not let your clients fall into the trap of tax avoidance
HMRC's 'Don't get caught out' campaign helps people working as contractors by empowering them to spot the warning signs of tax avoidance. It provides support for extricating from schemes and getting back on track if involved in tax avoidance.
HMRC have resources available to help your clients avoid the financial pitfalls of tax avoidance:
- Online guides that explain how to spot tax avoidance and a Short YouTube video explaining how umbrella companies operate.
- Interactive tools that help workers check if their contracts involve tax avoidance or review their payslips, so they can be confident they are paying the correct amount of tax.
- Real-life stories shared by people who want to help others steer clear of tax avoidance.
Contractors can also review HMRC's published list of named tax avoidance schemes and their promoters.
- This is not an exhaustive list and HMRC never approves such schemes.
Guidelines for compliance: ensure documents filed with HMRC are correct and complete
HMRC has recently published new guidelines to help ensure documents filed with HMRC are correct and complete. Taxpayers can ensure the information is correct and complete by:
- Checking their records.
- Reading HMRC guidance.
- If appropriate, consulting a professional advisor trained and competent for the task at hand.
The new guidelines are designed to help taxpayers when they:
- Remain uncertain of the correct interpretation of the law after making their best efforts to resolve that uncertainty.
- Are applying a novel interpretation of the law.
- Are considering applying an improbable interpretation of the law.
These guidelines are a practical product for taxpayers to refer to and they:
- Explain HMRC's view that a taxpayer should choose an interpretation of the law that is, on balance, most likely correct.
- Demonstrate the importance of all facts and views of the law being correct and complete to the best of a taxpayer's knowledge.
- Provide a recommended approach to professional advice.
- Help to resolve the remaining uncertainty.
- Cover expectations of advisers.
- Provide practical examples of legal uncertainty.
The new guidelines should be read alongside HMRC's existing guidance.
Self Assessment Class 2 National Insurance Contributions (NICs)
Work has been progressing to resolve the issue with Class 2 NICs affecting some Self Assessment taxpayers. The issue was first raised in Agent Update 133: July 2025.
- A technical fix is scheduled for deployment over the weekend of 27 and 28 September 2025.
- This means that all SA302 tax calculations issued from Monday 29 September will reflect the correct Class 2 NIC position.
Self-employed taxpayers who have already filed their Self Assessment tax return for 2024-25 will have their records checked and, if necessary, corrected before 31 January 2026.
- This will happen on a rolling basis and so HMRC are unable to share precise timings.
- Further updates will be provided as more information becomes available.
Taxpayers will receive updated SA302 tax calculations wherever corrective action has been taken.
- In instances where taxpayers have already paid an incorrectly applied charge, HMRC will ensure that the National Insurance position on their Self Assessment statement reflects the right amount and will adjust the amount of any further Self Assessment charge due this year.
When NICs should be paid on earnings for internationally or globally mobile employees
HMRC has updated its guidance to help employers determine when NICs are due on earnings paid to internationally mobile employees.
- Employees are internationally mobile if they:
- Live in the UK but work overseas.
- Come from overseas for periods of work in the UK.
- Are UK or overseas residents who move in and out of the UK to work.
- May work in several countries and have an employer based overseas.
While earnings are generally paid at the time the work is carried out, employees may receive later payments, such as bonuses, after they are earned.
- The updated guidance confirms that if the employee was liable for NICs at the time the work was carried out, they will continue to be liable for NICs in respect of those earnings, even if they are paid later when the employee has gone abroad.
See Globally mobile employees: National Insurance
How to correct NICs on earnings for internationally or globally mobile employees
Employers may find that they have either overpaid or underpaid NICs. Agents should advise their clients to use the following process where this is the case:
- Employers should make corrections through Real-Time Information (RTI) going back six years.
- Relevant evidence should be held to support any amendment, including:
- A record of the employees and their National Insurance numbers.
- Total amount and description of relevant earnings and amount of NICs already paid.
- When the relevant earnings were paid and the period over which they were earned.
- Amount of employee and employer Class 1 NICs now considered to be correct.
- Amount of NICs now due to be paid or refunded.
- An explanation of what caused NICs to be over or underpaid.
HMRC provides Guidance on how to correct the payroll through Full Payment Submission (FPS) and how to make a refund claim when employers have overpaid NICs and are unable to amend their RTI returns.
- Where a refund claim is being made, the employer will need to do the following, in addition to providing the above evidence:
- Use the reference 'NICs refund for Internationally Mobile Employees'.
- Provide the reason they cannot make the amendment through RTI.
Further information on How to make a voluntary disclosure to HMRC is available.
- Employers should use the reference 'NICs Disclosure for Internationally Mobile Employees' in their disclosure letter.
Large businesses with an HMRC Customer Compliance Manager (CCM) should notify them of any RTI corrections before making any refund claims.
- Voluntary disclosures being made by large business customers should be sent to HMRC in line with the existing process.
Where employees believe they are due a refund, they must contact their employer first.
- Any overpaid NICs by the employee should be repaid to the employee by the employer.
- If the employer has not submitted an RTI amendment or applied for a refund, their employees will need to provide the following information to HMRC:
- National Insurance number.
- Description of relevant earnings.
- When the relevant earnings were paid and the period over which they were earned.
- Reference that this is an internationally mobile employee case where NICs were overpaid.
- Class 1 NICs are being reclaimed.
- The reason their employer is not applying for the refund on their behalf.
Reserved Investor Fund (RIF) new online entry and accounting period information forms
HMRC have published two new online forms for RIF operators:
The online entry notice form replaces the temporary PDF form published in March 2025.
Update on Winter Fuel Payment recovery through the tax system
From Winter 2025, the eligibility criteria for Winter Fuel Payments in England, Wales and Northern Ireland, and the Pension Age Winter Heating Payment in Scotland, will be expanded so that more pensioners are eligible.
- If an individual has a total income of over £35,000, HMRC will recover winter payments through the tax system.
- A charge to Income Tax will apply that is equal to the full value of the payment received.
- For taxpayers under PAYE, HMRC will automatically collect the payment through a change to the taxpayer's tax code, unless they already file a Self Assessment tax return.
- This means their Winter Fuel Payment will be deducted from their income and paid to HMRC in monthly instalments across the 2026-27 tax year, starting from April 2026.
- For taxpayers under Self Assessment, the payment does not need to be included in this year's tax return.
- HMRC will automatically include the payment on their 2025-26 tax return, unless they file a paper tax return.
External link