THE British government had to borrow £2.6 billion sterling last month to balance its books, according to official figures published yesterday. That took the total public sector borrowing requirement (PSBR) for the first eight months of the current financial year to £13.9 billion, compared with £22.4 billion at the corresponding stage in 1995/96. The Treasury said the figure was fully consistent with the Budget forecast of a total PSBR this year of £26.4 billion.