Burnham inherits a fiscal buffer already shrinking beneath him
Burnham enters office committed to Reeves’s fiscal rules and the 2024 manifesto, inheriting the £23.6bn headroom she set at the March spring statement against Starmer’s defence plan, which spends £15bn while leaving £10.3bn to undecided departmental reallocation and £4.7bn to the autumn budget.
That headroom was measured before the Iran war and rising gilt yields began eroding it, and the £10.3bn of savings rests on reallocation decisions no minister has taken, so the fiscal rule Burnham adopts is only as sound as an OBR verdict that has not yet been issued.
Defence-exposed contractors get a clearer multi-year demand signal from the £15bn, while the suppliers and services tied to the departments absorbing the £10.3bn cannot yet price a cut whose distribution across government remains undecided.
The risk is not that the rules have already failed, but that Burnham’s fiscal room is now hostage to the OBR’s autumn scoring of energy, gilt yields and unfunded defence costs, forcing tax or spending choices before he has had much time to define his own economic programme.