UK national debt tops £3 trillion as interest costs put Burnham on track for near-record bill

Britain's national debt has crossed the £3 trillion threshold for the first time, according to the Taxpayers' Alliance Debt Clock, leaving the new administration with an annual interest bill of £109.3 billion, the fourth highest on record in real terms. The milestone arrived just over a fortnight after Andy Burnham entered Downing Street.

The pace of accumulation has accelerated sharply. It took 11 years to move from £1 trillion to £2 trillion during the 2010s; the latest trillion has been added in only six. Spread across every household, the headline debt now exceeds £100,000 before accounting for off-balance-sheet liabilities such as unfunded public sector pensions.

Interest burden compares with post-war peaks

Based on current Office for Budget Responsibility forecasts, Burnham is on track to oversee an average annual debt interest bill of £112.8 billion, second only to Rishi Sunak, whose term averaged £121.5 billion largely because of pandemic-era borrowing. Every year since 2022-23 now ranks among the four most expensive for debt service in the past seven decades, running at 2.4 times the long-run average.

Demographics drive unsustainable trajectory

The OBR's long-term projections show debt stabilising only until the early 2030s before climbing again on what the watchdog itself describes as an unsustainable path. State pension spending is forecast to rise from 5% to around 9% of GDP by the mid-2070s, driven by the triple lock, while health spending is projected to climb from 8% to 13% of GDP over the same period. The OBR has also acknowledged that its forecasts tend to become more optimistic the further out they extend, suggesting the true outlook may be worse.

Previous administrations have repeatedly argued that growth and reform would stabilise the debt ratio, but the pattern since the financial crisis has been one of persistent upward drift. Without a decisive shift, the interest burden will continue to crowd out spending on public services and investment, making any broader economic rebalancing considerably harder to achieve.

Read more on the debt milestone and its implications for defence spending.