Tax officials have admitted that they failed to collect £9.6bn of VAT returns in 2010-11 - the equivalent of nearly a third of the overall tax gap, the government's independent auditors have found.

The National Audit Office report also found that HM Revenue & Customs (HMRC) officials do not comprehensively check each registered company's VAT documents and have yet to produce a comprehensive plan for the emerging threat of VAT losses because of online trading.

According to the report, HMRC estimated that the tax gap for VAT in 2010-11 - the latest year for which the figures are available - was £9.6bn, while the total estimated gap (the difference between the amount of tax owed and the amount collected) is £32bn.