What happened?

The UK government announced on 28 October 2026 that it will legislate in Finance Bill 2026–27 to reduce the Advance Tax Certainty Service entry threshold from £1 billion to £300 million. The change would bring more major UK investment projects within reach of binding tax clearance.

Key details

HMRC measures qualifying UK expenditure over the project’s lifetime. Its service guidance already displays £300 million, but the Budget specifies 4 November 2026 as the intended effective date for the threshold and related penalty changes. This article reports an announced legislative measure, not completed enactment. The service launched on 1 July 2026. Transfer pricing is excluded; the separate advance pricing agreement programme remains relevant.

Who is affected?

Companies investing in qualifying UK projects, including overseas investors and qualifying joint ventures or consortia, should assess eligibility. A lower entry threshold does not itself guarantee clearance.

Effective date / timing

The announced threshold and penalty changes are intended from 4 November 2026; changes to the power for varying qualifying-project definitions are intended from 1 April 2027.

Business impact

T&M assessment: investors should map project expenditure, identify the tax uncertainties that could affect the investment decision and prepare evidence for early HMRC engagement. Clearance should be scoped to the actual project rather than treated as blanket approval of a group’s tax arrangements.