During this year's general election campaign, Labour has attempted to repeat their 2017 strategy of costing each commitment made in their manifesto. Given the sums involved, it seems only fair expect the party to lay out - in detail - what they are planning to spend and how they are planning to pay for it.
But perhaps this time, their so-called 'grey book' wasn't quite detailed enough. The party has been caught attempting to amend the costings document after its publication two weeks ago. In the original document, the shadow treasury team appear to have confused 'profit' with 'turnover'. Such a mistake will do nothing to allay the fears those who accuse the party of economic illiteracy.
In the document, called 'Funding Real Change', the party committed to maintaining a lower tax rate for smaller businesses as their corporate tax rate rises. Only those with a turnover under £300,000 would, according the initial costings document, be subject to this lower rate of tax.
This is not the first time Labour appears to have made the same mistake. Future leadership hopeful Rebecca Long-Bailey seems to have confused profit and turnover in a tweet from October. Perhaps, given all the money they're hoping to raise, a Corbyn government might be able to splash out on a proper accountant.