The monthly figure was lower than expected by economists, who had collectively predicted borrowing of £17.5bn for September.
“While tax revenue increased, this was outweighed by increased spending, partly due to higher debt interested and public sector pay rises,” said Jessica Barnaby, deputy director for public sector finance at the ONS.
However, the figure is still higher than was previously forecast by the Office for Budget Responsibility (OBR), which monitors the UK government’s spending plans and performance.
