Businesses using the Trader Support Service (TSS) to move goods between Great Britain and Northern Ireland need to prepare for a new platform launching soon. From 20 October 2026, all goods movements must be submitted using the new TSS platform.

Businesses are being asked to pre-enrol before the switchover. From 1 October, existing TSS users will receive an email explaining how to pre-enrol for the new platform. They will also be given access to a test environment so they can familiarise themselves with the new system before it becomes mandatory.

The TSS is a free digital service that supports businesses moving goods between Great Britain and Northern Ireland and helps them comply with the Windsor Framework.

Businesses will need to create a new password and check that their business details and permissions are up to date. HMRC says that updating a profile should generally take between 5-30 minutes, depending on the size of the business and the information available.

From 20 October, the existing TSS platform will no longer accept new goods movements. Businesses that have not completed the switchover could therefore be unable to submit declarations through the service.

The customs processes and legal obligations for businesses are not changing. However, the new platform is intended to provide improved functionality and support.

HMRC has published an updated list of deliberate tax defaulters. The list includes individuals, businesses and companies, detailing the amounts on which penalties are due and the exact penalties charged.

The details of a tax defaulter will be held on HMRC’s website for a maximum of 12 months from the date they are first published and are not stored within the National Archives.

The current list of deliberate tax defaulters (published on 24 September 2026) includes a Northampton-based business support company with an undeclared tax bill of over £9.1m and penalties of over £4.4m, alongside a retail sales company based in Nelson with an undeclared tax bill of almost £4.7m and penalties of almost £3.3m. There were also many smaller penalties listed for local trades and businesses, such as takeaways, convenience stores, letting agents, dog breeders, and mechanics.

A deliberate defaulter is defined as a person who incurs a relevant penalty for either deliberate errors in their tax returns or deliberately failing to comply with their tax obligations.

HMRC is legally permitted to publish these details where they have carried out an investigation, the person has been charged one or more penalties for deliberate defaults, and those penalties involve tax exceeding £25,000. Taxpayers who make an unprompted disclosure, or a satisfactory fully prompted disclosure, are not affected by these publication rules.

Businesses importing certain carbon-intensive goods into the UK will face a new carbon tax from 1 January 2027, when the Carbon Border Adjustment Mechanism (CBAM) comes into effect.

CBAM will apply to specified goods imported from outside the UK in the aluminium, cement, fertiliser, hydrogen, and iron and steel sectors. The tax is intended to put a comparable carbon price on imported goods to that paid by UK manufacturers. Not every product within these sectors is covered, so businesses will need to check the relevant commodity codes. This should help ensure that these UK decarbonisation efforts lead to a true reduction in global emissions rather than simply displacing carbon emissions overseas.

The person liable for CBAM will generally be the importer named on the customs declaration. Businesses importing CBAM goods will need to keep records, including information about the weight and emissions associated with the goods, and may need to register with HMRC.

A £50,000 threshold applies when determining whether registration is required. Businesses must monitor both a forward-looking test of expected imports over the next 30 days and a backward-looking test looking at the value of relevant imports over the preceding 12 months. If a person meets either test, they become liable to register.

The first CBAM accounting period will run from 1 January to 31 December 2027, with the first return and payment due by 31 May 2028. From 2028, accounting periods will transition to a quarterly cycle. For CBAM goods imported during the first calendar year of CBAM the backward looking test is only required to 1 January 2027.

Businesses importing potentially affected goods should check their position now and make sure they have the necessary records and systems in place before CBAM takes effect.

The tax treatment of some crypto assets is set to change under draft legislation for Finance Bill 2026–27. The proposed changes include new rules for qualifying stablecoins, crypto asset loans and liquidity pools.

Eligible stablecoins are expected to be treated more like money for Capital Gains Tax (CGT), Income Tax and Corporation Tax purposes. The government intends to introduce rules to provide greater certainty over how these assets are taxed, with the changes expected to apply from April 2027.

New rules will also apply to certain transactions involving cryptoasset loans and liquidity pools. Qualifying disposals will generally be treated as taking place on a ‘no gain, no loss’ basis for CGT purposes. This is intended to prevent a taxable gain or loss arising where there has not been an economic disposal of the cryptoasset.

The measures follow calls for clearer tax rules as the use of crypto assets continues to develop. HMRC has published draft legislation and supporting material for technical consultation, with further guidance expected before the new rules take effect.

The tax rules concerning what constitutes a distribution for tax purposes have remained largely unchanged since Corporation Tax was introduced in 1965. HMRC has recently published a consultation looking at possible changes to bring the rules more closely into line with modern commercial practices.

The consultation considers seven areas where the existing rules may create differences in tax treatment or uncertainty. The aim is to make the rules clearer and more consistent, while reducing unintended differences in tax treatment and the risk of errors and non-compliance.

The areas being considered include reductions of share capital, demergers, distributions from non-UK companies, loans to participators, purchases of own shares and the Transactions in Securities rules.

The consultation is mainly focused on shareholders within the charge to Income Tax, including individuals and trusts. The proposals are not intended to affect corporate shareholders directly.

HMRC also wants to ensure that genuine commercial activities and legitimate company reorganisations are not adversely affected and that the wider implications for growth and investment are taken into account.

For companies and their shareholders, the proposals are worth watching. They could ultimately affect the tax treatment of a number of transactions between companies and their owners, including capital reductions, company purchases of own shares and some company reorganisations.

At this stage these are proposals for consultation rather than confirmed changes to the tax rules.

The consultation closes on 14 September 2026. The government will then consider the responses and publish a summary. Further consultation may take place before any changes are introduced.

If you become liable to pay a tax or register for a tax that HMRC has not already been informed about, you must notify HMRC within the relevant time limit. Failing to do so can result in a financial penalty in addition to the tax and any interest due.

A failure to notify can arise in a range of situations, including when a business exceeds the VAT registration threshold, a company becomes liable for Corporation Tax or an individual first becomes liable to Income Tax when self-employment profits or investment income first arises. In some cases, businesses must also register before carrying out certain taxable activities.

HMRC calculates penalties according to the circumstances of the failure. Factors to be considered include whether the failure was deliberate, whether it was disclosed voluntarily before HMRC identified it, and how much assistance was provided during the disclosure process. Taxpayers who make an unprompted disclosure and fully cooperate with HMRC can often receive significantly lower penalties than those who wait for HMRC to discover the issue.

The level of penalty depends on the type of failure and the taxpayer’s behaviour. Penalties can range from a percentage of the tax liability that should have been reported, with lower penalties generally applying where a taxpayer makes a voluntary disclosure and cooperates with HMRC. Higher penalties can apply where the failure was deliberate or where HMRC discovers the issue before the taxpayer comes forward. In the most serious cases, penalties can be up to 100% of the tax due. HMRC will not normally charge a penalty where there is a reasonable excuse, provided the taxpayer notified HMRC without unreasonable delay after the reasonable excuse ended.

If you think you may have failed to notify HMRC of a tax liability, it is usually better to act promptly, and we would be happy to advise you. Coming forward voluntarily and providing complete information can reduce the level of any penalty and help resolve matters more quickly. 

What happens if you discover a mistake on your tax return? The good news is that errors can usually be corrected, but it is important to take action as soon as possible to avoid paying the wrong amount of tax or missing out on a possible refund.

If you realise that you have made an error after submitting your self-assessment tax return, you can normally amend your return within 12 months of the self-assessment filing deadline. The amendment can be made online or by submitting a revised paper return. For example, your self-assessment for the 2024-25 tax year can usually be amended up to 31 January 2027.

If you amend your return online, your tax calculation will be updated immediately and will show whether you owe additional tax or are entitled to a repayment. Any changes may also affect payments on account.

If the 12-month amendment period has passed, you will need to contact HMRC in writing. This applies if you need to report income that was missed from your return or if you believe you have paid too much tax and want to claim overpayment relief.

Overpayment relief claims can generally be made up to four years after the end of the relevant tax year. You must explain why you believe the tax has been overpaid, provide details of the amount involved, and confirm that the information provided is correct and complete.

After submitting your self-assessment return it is important to keep your records used to prepare the return. HMRC may ask to check your return, so it is important to keep the supporting documents and information used to complete your tax return.

There are no specific rules on how records must be stored. You can keep them on paper, digitally or as part of a software package, provided they remain accurate, complete and accessible if HMRC needs to review them.

If your tax return relates only to personal income, you should normally keep your records for at least 22 months after the end of the tax year they relate to. For example, records for the tax year ended 5 April 2026 should generally be kept until at least 31 January 2028. If you file your return late, records should be kept for at least 15 months after the date you submitted the return.

The records you should retain will depend on your circumstances but may include:

• employment records, such as P60s, P45s and P11D forms
• details of work expenses, including tools, travel and specialist clothing
• savings, investments and pension statements
• details of rental income and allowable expenses
• records of foreign income
• information relating to Capital Gains Tax
• details of state benefits and other taxable income

This is not a complete list. You should keep any records that support figures included in your tax return, including calculations and evidence for any claims or reliefs.

Different retention rules apply if you are self-employed or keep records for business purposes. Self-employed individuals must generally keep business records for at least five years after the 31 January filing deadline for the relevant tax year. Failure to keep adequate records can result in penalties from HMRC.