Nearly half of HMRC’s total workforce of 66,000 have been given access to Microsoft 365 Copilot licences since October 2025 in a 'staged expansion in weekly cohorts', taking six months to reach 28,000 users, after a trial in early 2024 to assess productivity, accessibility and risk.

This will see the 28,000 HMRC staff use the AI tool for day to day tax work including ‘official sensitive’ work.

HMRC will use a secure, enterprise version of the Microsoft 365 Copilot technology approved for use with information classified up to and including ‘official sensitive’, in line with UK government classifications.

Data is managed securely within HMRC’s IT systems and its use must comply with the tax authority’s security, data protection and acceptable use policies, HMRC confirmed, while a ‘phased and controlled approach to any further expansion, subject to governance, assurance and role suitability’.

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