This week’s miscellaneous updates – 29 September 2025

In this week’s detailed miscellaneous update which you can read more about below, HMRC has sent an update on the UK’s Pillar Two legislation. In other news this week:

• The use of AI by a taxpayer to support their appeal has been criticised in the Upper Tribunal case HMRC v Marc Gunnarsson [2025] UKUT 00247 (TCC),
• Meanwhile, in another Tribunal case, Elsbury v The Information Commissioner [2025] UKFTT 00915 (GRC), the First Tier Tribunal ruled that HMRC must disclose if and when AI was used in cases involving research and development tax reliefs,
• The House of Commons Library has published a research briefing exploring the National Insurance system, and the debate around integrating National Insurance Contributions with Income Tax, and a briefing which examines the way that Parliament scrutinises the Government's proposals for taxation as set out in the annual Budget statement has also been published, and
• HMRC has confirmed in an issue briefing that it has recommenced the use of direct recovery of tax debt from bank accounts.

Pillar Two update

Draft legislation was published in the summer for  amendments to the Multinational Top-up Tax and Domestic Top-up Tax for inclusion in Finance Bill 2025/26. According to HMRC, these amendments aim to ensure that the UK’s Pillar Two legislation is up to date with administrative guidance. The amendments also take into account previous stakeholder comments.

A guidance manual was also published on the UK’s Pillar Two rules. More information on the manual is available on the introduction page. HMRC invites any feedback from stakeholders on the manual.