HM Treasury
The most powerful department in Whitehall. Ministers come and go, policies rise and fall, but sooner or later almost every major decision ends up on a Treasury desk with a price tag attached.
The Treasury can stop almost anything a government wants to do. It controls tax, borrowing and spending. Ministers announce plans; the Treasury decides whether the money is there.
For decades, it has presented itself as the guardian of the public finances. The question is what all that guarding has done for the country.
The tax burden is forecast to reach 38 per cent of GDP by 2029/30, the highest since records began in 1948. Government spending is running at 44 to 45 per cent, its longest sustained period at that level since the Second World War.
Debt has risen from 32.4 per cent of GDP in 1999/2000 to 95 per cent today. Britain now has the fifth highest debt burden among 37 advanced economies, up from 21st at the start of the century.
Interest payments have climbed from £39 billion in 2019/20 to £106 billion in 2024/25. UK ten-year government bond yields are now the highest in the G7.
Despite all that tax and spending, Britain is still struggling to fund hospitals, schools, councils, defence and infrastructure. The Treasury has proved better at collecting money than producing the growth that would ease the pressure.
Annual productivity growth averaged 2.1 per cent between 1998 and 2007. It fell to 0.6 per cent between 2010 and 2019, then to 0.4 per cent between 2020 and 2024. That was the largest fall among G7 countries.
Had the earlier rate continued, GDP per person would have been about £15,000 higher in 2024. The United States has recovered some of its productivity growth since the pandemic. Britain has not.
The Treasury cannot be blamed for the financial crisis, pandemic or global energy shocks. Its response still deserves scrutiny. Maintenance was put off, capital projects delayed and council funding squeezed to improve the immediate figures.
Government investment remained below 2 per cent of GDP in almost every year from 1980/81 until the late 2010s. The current government has raised it above 2 per cent and plans to keep it there for the rest of the decade. Whether that survives the next fiscal squeeze is another matter.
Nine chancellors served between 1997 and 2024. Six came and went after 2016, none lasting three years. Plans to cut borrowing and stabilise debt have appeared in every forecast since the pandemic. The final figures have yet to deliver them.
Frozen tax thresholds and reduced allowances have also raised money without an explicit increase in headline rates. Decisions taken in the November 2025 Budget alone were forecast to bring in another £26.6 billion by 2030/31.
The Treasury remains good at preventing an immediate financial crisis. But productivity growth is down to 0.4 per cent, debt is at 95 per cent of GDP and interest costs £106 billion a year. Britain has paid heavily for standing still.