The government has written off £9.9bn of the £13.6bn it spent on personal protective equipment (PPE) in the pandemic due to the gear being unusable or having lost its value.
Accounts published by the Department of Health and Social Care (DHSC) also show the government has no idea exactly how much PPE it has stored.
"Nearly all" of the PPE held in warehouses or containers is set for disposal.
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DHSC said some of the PPE they had "was not usable by the department because it was defective or not suitable for use within the health and social care sector".
"Other PPE was not defective, but the department will not be able to use it before its expiry date," they added.
Gareth Davies, the head of the National Audit Office, said for the past two years, he had to limit his investigations because he was "unable to obtain sufficient, appropriate evidence to support the PPE recorded in the department's accounts".
He said the government estimates it would cost £70m to take a full stock-take of the PPE that is currently held.
Because of the change of market conditions and the state of the equipment, material the government spent £13.6bn on is now worth £3.7bn - a decrease of 73%.
In his report, Mr Davies notes the government has prevented and/or recovered £202m due to fraud associated with PPE procurement.
This is equivalent to 1.5% of the original £13.6bn spend, although DHSC "is still working to investigate and recover money from other potential cases of fraud and also contracts which failed to deliver".
Of the £202m, £139m was money DHSC prevented from being spent, while £63m has been recovered.
Mr Davies said that "ongoing efforts to detect, prevent and recover fraud must continue, improving public confidence that this drain on the public finances is being tackled effectively and efficiently".
Labour's shadow health secretary Wes Streeting said: "As chancellor, Rishi Sunak threw away taxpayers' money as if it were confetti, and has failed to get our money back. Sunak's carelessness has cost our country dear."
Liberal Democrat health spokeswoman Daisy Cooper added: "This is a sickening level of waste. Billions of pounds of taxpayers' money has been poured down the drain because of this Conservative government's incompetence."
Downing Street defended the losses, highlighting the circumstances in which the procurement took place.
Mr Sunak's official spokesman said: "It's important not to forget the circumstances in which the UK and countries globally found themselves during a pandemic when globally PPE was in extremely short supply.
"The costs as a result increased significantly, and the government took the decision very transparently to do everything possible to secure protective equipment for frontline health and care workers, that was right."