Rachel Reeves wants everyone to know that the Tories left the Treasury brassic

Brassic: adjective. Slang. Penniless, 'skint'.

the necessity of loading the blame on the Tories, at the start of a Labour government.

another reason for this is to instil some discipline amongst Labour MPs who are inclined to shout about their favourite spending plans. Spending will be done within a budget, not because somebody is shouting about it.