Data published by law firm Pinsent Masons has suggested that government tax investigations into large businesses are taking 'three and a half years' to complete.
According to the law firm, HMRC's litigation and settlement strategy makes it difficult for government investigators to settle for less than the full amount.
Commenting on the issue, a spokesperson for HMRC said: 'The tax we collect funds the UK's vital public services. We've secured over £62 billion in additional tax revenue from large businesses since 2010 – tax that would otherwise have gone unpaid.
'Over 85% of our investigations conclude within 18 months, but some cases are more complex and so will take longer to resolve and even require us to litigate.'
However, experts argue that tax investigations are often 'very disruptive' for businesses.
'HMRC's inflexible approach to tax avoidance is driving delays as it frequently aims to win every point against the business,' said Jason Collins, Partner at Pinsent Masons.
'HMRC's latest disclosure facility shows that HMRC is clamping down on what it views as businesses diverting profits from the UK through aggressive, out-of-date or erroneous transfer pricing.'