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Tooth, staleness and protective assessments

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What does the decision mean for protective assessments?

On 14 May 2021 the Supreme Court handed down its unanimous judgment in HMRC v Tooth [2021] UKSC 17, an important case on the validity of discovery assessments. Although the outcome was a victory for the taxpayer, any disappointment on HMRC's part will have been tempered by their success on the issue of 'staleness'.

Discovery assessments issued under TMA 1970 s 29 allow HMRC to recover tax after the normal time limits for opening an enquiry have expired if an HMRC officer 'discover[s]' that an additional amount of tax is due. This is a significant HMRC power and the relevant legislation therefore contains a number of conditions that must be met in order for the discovery assessment to be valid. As was seen in Tooth, where the taxpayer successfully argued that a condition that HMRC sought to rely on (essentially, that Mr Tooth's tax return contained a deliberate inaccuracy) had not been satisfied, whether the conditions have been met can form an important part of a dispute.

Prior to the Supreme Court's decision in Tooth, a series of decisions in lower courts developed the concept of 'staleness', which effectively created an additional, non-statutory restraint on HMRC's powers. The courts considered that a delay between an HMRC officer making a 'discovery' and the issuing of the discovery assessment may render that discovery 'stale' and the subsequent discovery assessment invalid. This notion derived from a judicial interpretation of the word 'discover' as something that 'newly arises'.

HMRC has steadfastly refused to accept that the concept of staleness exists. The Supreme Court has now made clear, departing from the Upper Tribunal and a majority of the Court of Appeal, that HMRC are right. The notion that a qualifying discovery could cease to be so merely as a result of the effluxion of time was, the Supreme Court held, 'unsustainable as a matter of ordinary language' and 'would conflict with the statutory scheme'. Whilst these comments were obiter dictum, it is difficult to see how any lower court could now take a different view.

Central to the Supreme Court's reasoning was that the statute provides sufficient taxpayer protection in the form of express time limits on HMRC's ability to raise a discovery assessment - generally four years, rising to six if the taxpayer has been careless, or 20 in respect of certain deliberate behaviour. These time limits run from the end of the relevant tax year and the Supreme Court found no basis for the imposition of an additional, stricter time restriction, based on 'staleness', running from when a discovery is made. The Supreme Court observed that an HMRC decision to make a discovery assessment was potentially subject to judicial review and, although it did not give its view on the practical application of that remedy, said that counsel for HMRC  accepted that, depending on the circumstances, a deliberate decision not to assess promptly might amount to irrationality sufficient to form the basis of a claim. This is unlikely to give taxpayers much comfort as, in practice, founding a successful judicial review claim based on delay by HMRC is likely to be very difficult.

Considering there is 'no place' for the additional time limitation imported by 'staleness', by similar logic, any non-statutory extension should also be impermissible. However, arguably, that is what HMRC's current practice of issuing 'protective' assessments shortly before the expiry of the statutory time limit achieves. Although HMRC says that a 'protective assessment' is only made where the statutory conditions are met, in practice, it is common to see assessments that lack detail and appear to have been hurried through before an approaching time limit. Therefore, a taxpayer in receipt of a 'protective' discovery assessment should scrutinise it carefully and bear in mind the fact that the burden of proof lies with HMRC to demonstrate that a discovery has indeed been made.

Taxpayers should not hesitate to challenge HMRC where it is considered that HMRC are extending their powers beyond statutory intention, or where HMRC may not be able to discharge their burden of proof.  The sun may have set on staleness, but procedural arguments regarding HMRC conduct are not going anywhere. 

Sophie Lloyd & Rob Smith, Travers Smith

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