The Autumn Budget comes at a pivotal moment for the UK economy. Growth has held up better than expected, inflation is expected to ease, and interest rates are likely to begin falling next year. Yet the combination of high public debt, elevated borrowing costs, and unfavourable debt dynamics make this a critical moment for the Chancellor.
Our analysis points to an underlying fiscal gap of around ?38 billion relative to the government’s rules. While this is somewhat larger than we expect the OBR to report in November, the broad message is the same: after years of successive shocks, the UK faces the urgent task of rebuilding fiscal headroom. Beyond closing any gap the OBR identifies relative to the fiscal rules, the government should build in an additional safety margin of at least ?30 billion to provide genuine insurance against future shocks.
But the central issue is not the fiscal rule itself ? it is debt sustainability. With borrowing costs now exceeding the long-run growth rate of the economy, stabilising the debt ratio requires running sufficiently large primary surpluses ? that is, running budget surpluses before interest payments. Larger surpluses are needed to start bringing debt down. Without such an adjustment, debt dynamics act as a ratchet: each new shock lifts the ratio higher, and without determined consolidation, it never falls back.
Five years on from the pandemic, this is the moment to start reversing that drift. The economics are clear; what is required now is political will ? the readiness to take difficult decisions on tax and spending in the long-term interests of the UK economy.