The recent Institute for Fiscal Studies report, 'The public sector workforce: past, present and future', suggests that general government employment will fall to about 15% of the workforce. 

This is about half the proportion in Norway and Sweden, which operate to a high tax and high service model of the state, but it is also below many other developed countries - particularly when adjustments are made for those which do not run healthcare through the state.

The report also says that, if the NHS and schools continue to be protected, employment in other parts of the public sector will have to bear the brunt of the cuts.  However, it is possible to be more specific.