The Government is being urged by MPs to publish a list of companies which have signed up to the furlough scheme amid concerns it does not know how much is being lost through fraud and error.

The Commons Public Accounts Committee said levels of “opportunistic fraud” – where furloughed staff continued to work while companies claimed grants – could be running at between 7% to 34% of cases.

However under current plans, the true scale of the losses will not be disclosed until the end of next year at the earliest.

The committee called on HM Revenue and Customs (HMRC) to release a list of employers which have received funding from the scheme by the end of January.

At the same time, it said HMRC and the Treasury should do more to help the estimated 2.9 million workers who have been excluded from both furlough and the income support scheme for the self-employed.

As of October, the two schemes had cost more than £55 billion, but since then they have been extended into 2021 with the furlough scheme now set to run to the end of April and the self-employed support continuing to the end of January.

While the Office for Budget Responsibility has estimated the increased costs at £21 billion, the committee expressed concern the Treasury has not even been able to give a “ballpark figure” or to explain how it would determine whether the spending represented good value for money.

Despite the extensions following the national lockdown in England in November, the committee said the Government had not developed its methods for determining whether people are eligible to ensure assistance gets to all those who need it.

With the Treasury claiming it can’t give even a ballpark figure for the cost of Covid job support until the end of next year, public scrutiny of where taxpayers’ money is going is essential

“HM Treasury and HMRC should investigate whether more data within and outside of the tax system could be used to determine eligibility for currently excluded groups and write to the committee within six weeks to explain their findings,” the committee said.

The committee chair Meg Hillier said that with so much taxpayers’ money going to private companies, it was essential that there was full transparency.

“With the Treasury claiming it can’t give even a ballpark figure for the cost of Covid job support until the end of next year, public scrutiny of where taxpayers’ money is going is essential,” she said.

“Many workers including freelancers and entrepreneurs have not had a penny and are really struggling as they continue to fall through the gaps.

“There is data that could be crunched to reach and help these individuals, many of whom will be unable to work at all under Tier 3 restrictions.”