Move head of Treasury? That’s the Chancellor’s plan (6)
I believe the answer is:
budget
'the chancellor's plan' is the definition.
(I've seen this before)
'move head of treasury?' is the wordplay.
'move' becomes 'budge' (to budge is to move slightly).
'head of' suggests taking the first letters.
The first letter of 'treasury' is 't'.
'budge'+'t'='BUDGET'
'that's' is the link.
(Other definitions for budget that I've seen before include "Financial estimate" , "Fiscal estimate" , "Plan for expenditure and fund allocation" , "Plan of spending" , "Funding plan" .)