A report by MPs has said the government's NHS Test and Trace programme (NHSTT) "has not achieved its main objective", which was to ensure people were able to return to normal life as quickly as possible.
The report said the scheme had been handed “eye-watering” sums of money, which totals to 20% of the NHS's entire annual budget.
Dame Meg Hillier, the chair of the Public Accounts Committee (PAC), criticised the government's management of the NHSTT, saying part of the issue was due to overconfidence.
"There was a lot of gung-ho confidence from No 10 that we would have a ‘moonshot’ towards mass testing," she told the BBC. “Those messages kept getting more optimistic.
"Baroness Harding was also very optimistic about what they achieved."
She also said the government had played fast and loose with taxpayer money.
“But in the end it massively over-promised for what it delivered and it was eye-watering sums of money.
“That is one of the biggest concerns – it is almost as if the taxpayer was an ATM machine. That lack of regard for taxpayer funding is a real concern for us as a committee."
The PAC described the costs of the system as "unimaginable", and said it must "wean itself off persistent reliance on consultants".
Expensive contractors have been a subject of fierce criticism with the average salary at around £1,100 per day.
"The continued reliance on the over-priced consultants who ‘delivered’ this state of affairs will by itself cost the taxpayer hundreds of millions of pounds," said the committee's chair.
The committee also said the system was failing more vulnerable people who used NHSTT less frequently, and called for a “proper long-term strategy”.
The government's COVID tracing scheme has a budget of £22bn, with a total of over £37bn over two years – equal to 20% of the NHS's yearly budget.
The government came under fire in 2020 after Test and Trace contracts were given to companies without competition, and Matt Hancock was found to have acted unlawfully in failing to publish multibillion-pound contracts within the legally required 30-day period.
The committee say just 14% of the 691 million lateral flow tests sent out reported results, and it's unclear how many people isolated if they received a positive test.
Dr Jenny Harries, chief executive of the UK Health Security Agency (UKHSA), said: “NHS Test and Trace (NHSTT) has played an essential role in combating this pandemic and said there had been improvements. More than 323 million tests have now been carried out across the UK.
"NHSTT has now contacted more than 19.9 million people, helping to slow the spread of the virus," she said.
“Testing, contact tracing and the wall of defence built by our vaccination programme are all fundamental to our ongoing efforts to keep people safe as we return to a more normal way of life.”
The government have responded defensively to the committee's findings, especially on criticism over the use of consultants.
“We have rightly drawn on the extensive expertise of a number of public and private sector partners who have been invaluable in helping us tackle the virus," it said in a statement.
Watch: Former minister Robert Jenrick admits Test and Trace failures 'concerning'