In 2025, the former Greater Manchester mayor created a £1bn “Good Growth Fund” for the region, financed by local government pension pots, government grants and cash from Rachel Reeves’ National Wealth Fund. Instead, changing tax revenues kept by local leaders may need to be based on more than the size of local income, or how local income grows over time. A framework based on sharing a flat portion of income tax receipts generated locally could be volatile on a year-to-year basis and make local tax systems over-reliant on the wealth of higher income tax rate payers.