It is easy to assume as a layperson that when HMRC challenge you, they are right. Penalty notices, tax assessments, enquiry conclusions - all routine areas where in one way or another, HMRC come to a conclusion about how you have conducted your affairs, or the way rules apply, and reach a decision that can cost substantial sums of money.

To err is to be human and, alas, despite HM Government's glacial attempts at digitising tax, HMRC remains full of humans. So, unsurprisingly, it remains full of errors.

One such example was laid out brutally. The First-Tier Tribunal case of Pavan Ltd (TC08712) heard an appeal against an assessment to VAT. The underlying technical aspects are complicated, and irrelevant to our point.

In this example, HMRC pursued an assessment for additional tax based on their interpretation of obligations placed on a taxpayer. That interpretation was wrong, plainly so it turns out according to the First-Tier Tribunal. When challenged, albeit later than one would hope, HMRC's approach failed and the error was exposed.

Nobody in the chain of financial process and information from taxpayer to HMRC, including accountants and other agents, are perfect and mistakes do occur. Whilst I'm sure the Directors of Pavan Ltd would have hoped HMRC would realise their errors a little earlier, the point is this: they happen.

If HMRC reach a decision relating to your tax affairs - a penalty notice, a tax assessment or an enquiry conclusion - make sure you understand the decision. If you don't - ask - seek support from professional advisers. Sometimes it's clear cut, but sometimes it isn't, and we all have a bad day at the office.