We can get some indication from a recent NAO report (Central government staff costs, 2015) which used
unpublished Cabinet Office data to calculate that the total annualised salary cost for the civil service in 2014 was # 11.13 billion, a decrease of # 2.49 billion in real terms on 2010.
For public bodies included in the analysis, the NAO noted that the
Cabinet Office used
unpublished data and methodology that the NAO could not replicate (although the NAO said that the figures that it calculated by other means were roughly comparable).