UK government finances showed a surplus of £8.8bn in January, the Office for National Statistics (ONS) has said.
It is the highest surplus for seven years and higher than the revised £6.5bn reported for January 2014.
A better than expected rise in tax receipts means the government is on course to meet its borrowing target for this year.
The surplus means borrowing has fallen to £74bn in the financial year to date, a fall of £6bn compared with last year.
The government's borrowing target for the 2015 financial year is £91.3bn.
January's public sector finance data traditionally shows a surplus, as it includes tax receipts from those who submit self-assessment forms.