UK Borrowing Surges to £24.5 Billion in September, Debt Exceeds £3 Trillion

UK government borrowing surged to £24.5 billion in September 2026, exceeding forecasts and pushing the total national debt past £3 trillion for the first time[1][7][8]. This marks a £1.8 billion increase from September 2025 and is £1.9 billion higher than the Office for Budget Responsibility's (OBR) prediction[8][10].

This unexpected financial strain significantly reduces the fiscal flexibility for Chancellor John Healey, who is set to deliver his first budget on October 28, 2026[1][2][5]. The increased borrowing and debt interest payments have reportedly halved his fiscal headroom, forcing difficult decisions on public spending and taxation[3].

What the records show

The Office for National Statistics (ONS) announced on October 21, 2026, that public sector net borrowing reached £24.5 billion in September[1][11]. A significant factor was a record £10.9 billion paid in debt interest during the month, the highest September figure since records began[1][7][11]. Approximately £4 billion of these interest costs in September alone are attributed to rising inflation, specifically the Retail Prices Index (RPI), to which some government bonds are linked[7]. The ONS noted that the conflict in Iran has contributed to rising energy costs and RPI[7].

For the first time, total government debt surpassed £3 trillion at the end of September 2026, reaching a provisional estimate of £3,005.0 billion[7][8][11]. Despite this, public sector net debt as a proportion of the economy decreased slightly to 94.0% of GDP, a 0.7 percentage point drop from a year earlier[8].

The timeline

Andy Burnham became Prime Minister in July, subsequently appointing John Healey as Chancellor[5]. Healey delivered speeches in Coventry on September 7, 2026, and at Labour's conference on September 28, 2026[3]. The ONS released the September borrowing figures on October 21, 2026[1][11]. Chancellor Healey is scheduled to present his inaugural budget on October 28, 2026[2][3].

What changed and for whom

The surge in borrowing and debt interest payments has significantly tightened the fiscal position for Chancellor Healey[1][3]. Estimates suggest his buffer against the government's self-imposed fiscal rules has been reduced to approximately £12 billion, which is roughly half the level forecast by the OBR in March[3]. This reduction in fiscal headroom means Healey faces a more challenging environment for his upcoming budget, limiting options for spending and tax decisions[3].

What the subject has said publicly

Chancellor John Healey has consistently emphasized fiscal discipline since his appointment[3]. Speaking in Coventry on September 7, 2026, and again at Labour's conference on September 28, 2026, Healey stated that "fiscal credibility is indivisible from growth"[3]. He has committed to meeting the government's fiscal rules[3].

What we could not confirm

Specific new policy measures or tax changes that Chancellor Healey will announce in his budget could not be confirmed, although analysts anticipate potential increases in bank taxes[3][10]. The precise impact of current economic conditions on the final fiscal headroom also remains subject to ongoing analysis[3].