The OBR's October 2026 Economic and Fiscal Outlook (Table 3.1) shows Budget tax measures raising £7.5bn in 2031-32, the final forecast year, below £10bn; obr.uk is blocked by Cloudflare, so the same OBR document was read in the copy laid before Parliament on gov.uk, and BBC News noted nearly all 98 measures were small.
The market resolves on the OBR's Economic and Fiscal Outlook published on obr.uk on 28 October 2026; YES if its policy-decisions scorecard shows net tax policy measures raising at least £10bn a year in the final forecast year. The OBR scorecard is the single canonical source and HM Treasury's own tables are corroborating record only; if the EFO text states a headline net tax-rise figure for the final forecast year, that figure governs. By 23:59 GMT on 28 October 2026. If that source has not published in time, BBC News and the Financial Times reports of the scorecard settle it.
We found four times since 2008 when UK borrowing ran above the official forecast in the months before a chancellor's next Budget or big statement. For each, we checked whether that event raised taxes overall or set out a plan to cut the deficit. This year's overshoot is the one being tested, so it is not among the four.