Public sector borrowing rose to £14.2bn in November, missing expectations of £11.8bn and rising higher than this time last year, when the UK borrowed £12.9bn.
The figure suggests the Treasury is likely to miss a full-year target of £73.5bn set by the Office for Budget Responsibility (OBR), analysts suggested.
"Barring a dramatic improvement in the trend, [the target] is looking likely to be missed by possibly more than £5bn," said James Knightley, senior global economist at ING.
The good news was that government income rose by one per cent on last year, to £46.3bn. However, central government spending rose to £58bn - three per cent higher than the same period in 2015.
Just under two-thirds of spending was by government departments and a third went on social benefits, while the remaining amount was spent on capital investment and interest on government debt.
"The November public finances provide little festive cheer for the chancellor," said Howard Archer, chief UK and European economist at IHS.
"The chancellor now faces a massive task to meet his fiscal targets for 2015/16 and it is frankly hard to see how he can make it - even allowing for the fact that public finances can be volatile from month to month.... [and] the OBR argues that there should be a substantial improvement in the public finances in the final months of 2015."