Britain’s public finances are in a desperate state. That is the key message the chancellor, Rachel Reeves, will deliver in a speech on Monday, which she will use to draw attention to a £20bn black hole in the tax and spending plans bequeathed to her by the last government.

Critics will say that this should not be news; it was patently obvious that the Conservatives cooked the books before the last election, baking in impossible-to-achieve spending cuts in order to make their plans for the next five years seem plausible. That did not stop Labour adopting the Tories’ projections as its baseline, because it suited the party politically. However, Reeves would be entirely correct in arguing that the unenviable inheritance is as much a product of Conservative neglect and incompetence as it is of external shocks, and that Labour could not know the full extent of the fiscal gap until it was in government and had the opportunity to examine the books carefully.

The most important question is what she will do about it. She faces a toxic mix: an economy characterised by sluggish productivity growth, weakened by decades of insufficient business investment, and made worse by the uncertainty, and the trade barriers, occasioned by Brexit. Meanwhile, Britain’s public services are in urgent need of investment: from the NHS, plagued by record waiting lists, to schools struggling to........

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