Other news in brief

On 30 April 2026, the OECD released a Global Minimum Tax (GMT) Implementation Toolkit  and updated GMT Frequently Asked Questions (FAQ). The Toolkit is primarily aimed at tax administrations implementing GMT but may help businesses in two ways:

• By illustrating the variation and divergence in local rule interpretation and application of the GMT, a key focus area ahead of the June 2026 filing deadlines; and
• By calling for grace periods for return correction, penalty relief and return-filing extensions where merited, though it remains to be seen whether administrations follow this advice.

The FAQ document is a refresh of an earlier version and includes 27 questions divided across five sections. Two sections deal with the basic GMT charging and calculation rules (and largely replicate the content from the earlier FAQ document), with the remaining three sections dealing with the Side-by-Side Package. In particular, the FAQ document considers the treatment of income-based tax incentives under the Substance-based Tax Incentive Safe Harbour as well as changes in the allocation key for Blended CFC Taxes from January 2026. KPMG’s EU Tax Centre has published a high level summary of these two publications and, for readers looking for more information, KPMG International has published a detailed report. 

The launch date for HMRC’s new Advance Tax Certainty Service (ATCS) is approaching and, in anticipation of this, on 12 May 2026 HMRC published a new landing page for the service providing a more user-friendly initial summary of the regime than the existing draft guidance/consultation page. More details on the ATCS can be found in our earlier article published when detailed draft guidance had just been released. That draft guidance has not yet been finalised but is expected to be shortly. The most noteworthy content in the new landing page is information on the delivery timeline:

• The page confirms that the ACTS will formally launch on 1 July 2026, providing some additional clarity to earlier commitments made to launch in ‘July 2026’; and
• HMRC will also start taking expression of interest meetings for prospective users of the ATCS service from 1 June 2026, which they hope will help to progress service delivery quicky after launch.

On 11 May 2026, HMRC published a new policy paper for inheritance tax on pensions. This technical note provides details on the practical operation of the new legislation included within Finance Act 2026, which is effective from 6 April 2027. Following some speculation, the note confirms that where both income tax and inheritance tax apply on death, the portion of the benefits corresponding to the inheritance tax (and interest) paid does not count towards the beneficiary’s taxable income, regardless of how the inheritance tax is paid. In effect, this suggests that in all cases the maximum effective rate of tax would be capped at 67 percent (i.e. if 40 percent IHT is paid on £100 of pension benefits, then £40 will be excluded from income tax – but the remaining £60 will be fully subject to income tax, meaning that if the recipient is a 45 percent taxpayer he/she will pay £27 income tax, resulting in a total overall tax bill of £67). It also confirms HMRC’s view on the normal expenditure out of income inheritance tax exemption, stating that the changes “do not alter the existing position for lifetime transfers”, so each case should be tested against the exemption criteria.

Finance Act 2026 introduces a new requirement for tax advisers to register with HMRC which, as explained in our recent article, will potentially apply quite widely; capturing some in-house tax teams in corporate groups, law firms, financial institutions, asset managers and family offices. At the time of writing, the three-month registration period is expected to commence on 18 May 2026, although the statutory instrument confirming commencement and some limited deferrals (notably the expected postponement of the registration deadline for financial services organisations to 31 March 2027) has yet to be published. On 30 April 2026, HMRC published further guidance albeit only in two limited areas: guidance on what to do if you disagree with HMRC's decision about your tax adviser registration and guidance on what happens if you interact with HMRC when you are unregistered or suspended as a tax adviser. However critical guidance, for example, on the definition of relevant individuals, still remains outstanding creating uncertainty for organisations affected whilst the planned start date is almost upon us.

The National Insurance Contributions (Employer Pensions Contributions) Bill was introduced following an announcement in Autumn Budget 2025 to provide for a cap from 2029/30 on pension salary sacrifice contributions that attract NIC relief. After completing its passage through Parliament, the Bill received Royal Assent on 29 April 2026 and has now been published as the National Insurance Contributions (Employer Pensions Contributions) Act 2026.

HMRC have added synthesised text of the Multilateral Instrument and the UK-Pakistan Double Taxation Convention and the UK-Indonesia Double Taxation Agreement to the collection of published tax treaties on their website. The synthesised text reflects the changes made to those treaties by the OECD’s Multilateral Convention to Implement Tax Treaty Related Measures to Prevent Base Erosion and Profit Shifting (commonly known as the Multilateral Instrument or MLI).