Public sector net borrowing rose to £20.2 billion for the month, £1.6 billion higher than in September 2024, the Office for National Statistics said.

Rising debt interest costs, pay rises and inflation increasing the Government’s day-to-day running costs, and inflation-linked benefit increases all helped push up the Government’s deficit last month.

This more than offset the amount that was raised through tax and national insurance.

The figure means the Government spent more on the public sector than it received in taxes and other income in September, requiring it to borrow billions of pounds.

September’s borrowing was lower than the amount most economists had been expecting at £20.8 billion.

However, it came in slightly ahead of the £20.1 billion the UK’s independent fiscal watchdog, the Office for Budget Responsibility (OBR), had forecast in March.

August’s borrowing figure had also been the highest recorded for that month since the onset of the Covid pandemic.

Furthermore, borrowing in the current financial year, between March and September, hit nearly £100 billion.

This was the second-highest amount since monthly records began in 1993, after that of 2020, the ONS said.

ONS chief economist Grant Fitzner said: “Last month saw the highest September borrowing for five years.

“Debt interest, the cost of providing public services and benefits all increased compared with last year, more than offsetting the rise in receipts from central government taxes and national insurance contributions.

“Likewise, the first six months of the financial year saw the highest overall deficit since 2020.”

Chief Secretary to the Treasury James Murray said: “This Government will never play fast and loose with the public finances.

“We know that when you lose control of the public purse it’s working people who pay the price.

“That’s why we plan to bring down borrowing and, according to IMF (International Monetary Fund) data, are set to deliver the largest primary deficit reduction in both the G7 and G20 over the next five years.

“We are cutting waste, improving efficiency and transforming our public services for the future so that we can be rid of costly debt interest, instead putting that money into our NHS, schools and police.