HMRC Connect — the UK Tax Authority's Data-Analytics Engine, Reported at About £4.6 Billion Extra Yield in 2024-25

Connect is HMRC's analytics system, introduced in 2010 and grown over 15 years into one of the largest datasets held by the UK government. It draws on data from a range of financial sources to analyse tax returns and flag potential evasion for compliance staff.
According to a Freedom of Information response reported by Pinsent Masons in October 2025, about 4,300 HMRC staff use Connect, it supported more than 500,000 cases in the latest year, and it generated about £4.6bn in additional tax in 2024-25 against an average of about £3.4bn a year. HMRC also confirmed a partnership with a US analytics firm intended to bring more advanced AI into its data work.
The evidence is thinner than the headline: the figures come from an FOI reply, not a published, audited HMRC report; it is not stated whether yield is gross or net or how it is attributed to Connect versus other methods; and the 2019 ministerial figure cited was about £1.4bn. Little is public about safeguards, error rates or taxpayer redress, so the case is best read as a large-scale, self-reported enforcement tool whose independent evaluation remains outstanding.

Read the full analysis: https://www.pinsentmasons.com/en-gb/out-law/news/hmrc-big-data-tax-revenue-boost-4-6-billion