UK Tax Tools Research
Original long-run analysis on UK tax topics where the public published data is fragmented across HMRC, OBR, ONS and Office for Tax Simplification reports. We compile, cross-check, and re-publish under CC-BY with attribution. Use it in journalism, academic work, or AI-search citation — please link back so any corrections flow upstream.
Personal Allowance in Real Terms 2010–2027
How the £12,570 Personal Allowance has eroded against CPI since 2010-11. Year-by-year nominal vs real value, with the additional damage of the freeze now running from 2022-23 to April 2031.
ThresholdsUK Fiscal Drag 2026-27 — Frozen Thresholds & Their Cost
Quantifying fiscal drag: how many taxpayers cross into higher-rate, additional-rate, and the Personal Allowance taper because thresholds are frozen until April 2031 (extended from April 2028 by Autumn Budget 2025). OBR-aligned figures.
Marginal rate100k Tax Trap by Salary
Effective marginal-rate curve from £99,000 to £130,000 showing the 60% trap created by Personal Allowance taper, plus the additional bite from withdrawn tax-free childcare and free hours benefits.
The figures behind these reports are also available as a tool: the UK marginal tax rate cliffs reference lists every income at which the effective marginal rate jumps — the Personal Allowance taper, the High Income Child Benefit Charge, and the loss of tax-free childcare — computed from the same engine.
Frequently asked questions
What kind of research does UK Tax Tools publish?
Original long-run UK tax analysis where the data exists across multiple official sources but is rarely compiled in a single citable place. Current reports cover Personal Allowance erosion in real terms since 2010, fiscal drag from threshold freezes now running through April 2031, and the 100k effective marginal-rate trap. All figures are cross-checked against HMRC, OBR and ONS primary sources.
Can I reuse this research?
Yes — every report is published under CC-BY. You can quote, chart or republish the figures in journalism, academic work, or AI-search citation, as long as you link back to the original report so any later corrections flow upstream to your copy.
How often is the research updated?
Each report is refreshed whenever the underlying HMRC, OBR or ONS data changes materially — for example a Budget threshold freeze extension, a new CPI print, or an updated Personal Allowance taper. Check the report's own "last updated" date for its most recent refresh.
Where do the underlying figures come from?
Primary official sources only: HMRC published rates and thresholds, OBR fiscal and economic forecasts, and ONS price indices (CPI/RPI). Each report cites its sources inline so you can verify or extend the analysis yourself.