β οΈ
CONTESTED ESTIMATE
Significant methodological disputes. View caveats below.
π°Fiscal
Laffer Curve Tax Cuts
Upfront
Β£0m
Annual
-Β£45.0bn
Revenue
+Β£7.5bn
Net Annual Effect
-Β£37.5bn/year
GDP +2%Productivity +0.4%very high uncertainty
UNCERTAINTY RANGE (Annual Net Effect)
Most Pessimistic
-Β£60.0bn
β·
Most Optimistic
-Β£20.0bn
β οΈ
MAJOR CAVEATS
- β’Static vs dynamic scoring contested: OBR uses static, but 2024-25 receipts below forecast after tax rises
- β’Laffer curve position uncertain: record millionaire exodus (UK now global leader) and non-dom flight suggest behavioural response stronger than models predict
- β’Elasticity assumptions vary widely: academic models (0.1-0.3) vs observed capital flight response
- β’International evidence mixed: Ireland corporate tax success, UK 50p rate underperformed, Kansas cuts failed (context-dependent)
- β’Transition costs real: static cost Β£40-50bn/yr requires offsetting measures or borrowing
- β’Counter-evidence: UK highest tax burden since 1948 correlates with stagnant growth, not revenue maximisation
4 sources
