Almost half the letters sent to the Treasury by MPs and peers are not responded to within the target time of 15 working days, figures revealed today.
George Osborne's Treasury is the worst performing main department on Whitehall after it answered 53% of 16,539 letters received last year within its own time limit.
Across all of Government, only Ofwat performs worse, responding within its target time only 39% of the time. The quango has a shorter limit of 10 working days but only received 108 letters last year.
Michael Gove's Department of Education responded within its 15-day time limit only 55% of the time after receiving 16,413 letters.
The figures were released in a written statement to MPs by Paymaster General Francis Maude.
Mr Maude's figures revealed only two central Government bodies hit their correspondence targets 100% of the time - the Treasury Solicitor's Department, which received 16 letters, and the Child Maintenance and Enforcement Commission, which received 1,956.