It’s very unlikely. However, if you’ve underpaid, we’ll ONLY tell you, not HMRC. You should then inform HMRC as when they spot you’ve underpaid at a later date through their own system, they’re likely to charge you interest and penalties so it’s in your interest to contact them, but we can’t insist you tell them.

We also have an underpayment guarantee – we guarantee if you get an unexpected tax demand as a direct result of our work, we will pay any tax owed as a result of our error (T&C’s available here).