The language is descriptive; the tone is dry. The authors are auditors and civil servants, and their evaluation of universal credit will have been scrutinised by Department for Work and Pensions officials before its release. But there is no mistaking the meaning of today’s report. Eight years after the flagship welfare project was launched by Iain Duncan Smith, the verdict from the public spending watchdog is in: it is a fiasco.

Not only is it not working now, after £1.9bn has been spent. The National Audit Office sees no reason to believe that it ever will. The original promise, that 300,000 unemployment benefit claimants would get jobs, is impossible to measure. The savings supposed to be generated by efficiency and the reduction of fraud have not materialised. These two pledges – that more people would work; that public money would be better spent – were the point of this programme. That neither is deliverable is a disaster.

But it gets worse, because the NAO also says there is no way back. With 10% of 8 million claimants moved across to universal credit so far, on two separate pathways involving different software, and more than 7 million to follow, we are stuck between a rock and a hard place. As the work and pensions select committee chair, Frank Field, put it, there is now a “mega cost to scrap it and a mega cost to the taxpayer to continue”.

Just how mega depends on whether the DWP’s predictions about what happens next turn out to be right – whether, for example, the cost per claim plummets from £699 to £173, and the number of claimants verifying their identities online shoots up from 38% to 80%. The NAO’s verdict on such optimistic projections: “Universal credit may cost more to administer than the previous system of benefits it replaces.”

The human misery brought about by the changes requires a different form of accounting. Yesterday the high court ruled in favour of two severely disabled men whose benefits were cut when they moved into a universal credit area. The government is applying to appeal.

This will surely not surprise the auditors, whose report draws attention to the defensive, combative stance taken by the DWP towards its critics – and taken again today in a statement insisting that everything is “on track”. Since the Guardian’s first reports on the pilot areas in 2015, it has been clear both that there were flaws in the system’s design, and that some claimants were finding it difficult to navigate. The inbuilt delay of five weeks before the initial payment is one problem, since this leaves people without any money. Another issue is rent. Whereas housing benefit was paid direct to landlords, universal credit is paid to claimants, and there is evidence that increasing numbers have found themselves in arrears.

That the DWP doesn’t want to know about any of this is all the more shortsighted since there was, and remains, a cross-party consensus that a simpler benefits system is a good idea (and Liberal Democrats were in the cabinet alongside the Conservatives when it began). There are principled objections to the new regime, as well as to the cuts that have exacerbated its punitive aspects. But the government can no longer dismiss all criticism as political. It has to get a grip. Since Mr Duncan Smith resigned in 2016 there have been four work and pensions secretaries. Esther McVey has been in post just a few months, as has the permanent secretary Peter Schofield. As a first step, the government must admit that it has got universal credit wrong, and set about limiting the damage.