Unprotected Whitehall departments have been ordered to 'wargame' 10% budget cuts for the 2015/16 spending round – a potentially massive one-third cut in public service expenditure – the Treasury has confirmed.

A series of individual notes, sent last week by chief secretary to the Treasury Danny Alexander to departments, lists areas of waste he would like to see addressed ahead of the 26 June spending review – with a view to making £14.5bn resource budget savings.