Can I reduce HMRC penalties by cooperating?

HMRC's penalty regime is built to reward cooperation, not just punish error. Once your behaviour category and disclosure type set the outer range, the actual percentage within that range depends on how much you help HMRC.

The framework breaks cooperation into three strands: telling HMRC about the inaccuracy and why it happened, helping them work out how much tax was lost, and giving them access to check the figures, for example by providing records or agreeing to a meeting.

Score well on all three and the percentage can fall to the bottom of the range for your behaviour and disclosure type. Score badly, or stay silent, and HMRC can apply close to the maximum.

This reduction sits within Schedule 24 Finance Act 2007 and the equivalent provisions in Schedule 41 Finance Act 2008 for failure-to-notify cases. HMRC's Compliance Handbook sets out internal guidance for how caseworkers should weigh each of the three elements.

Telling typically carries the greatest weight, because volunteering the full picture unprompted, or as soon as possible once prompted, does the most to reduce HMRC's own investigative burden.

Helping and giving access are judged on responsiveness and completeness rather than volume. Sending everything requested promptly, in a usable format, counts more than sending a large amount of disorganised material slowly.

As the person usually corresponding with HMRC on the company's behalf, your conduct during the enquiry directly shapes this part of the calculation. Late replies, incomplete answers or repeated requests for extensions can all be read as poor cooperation.

It helps to appoint an accountant who understands what HMRC actually wants to see, so records are provided once, in the right form, rather than in a drawn-out back-and-forth that looks like resistance.

If you discover additional errors during the enquiry that HMRC hadn't asked about, disclosing them voluntarily, rather than waiting to be asked, is treated as strong cooperation and can meaningfully improve the final percentage.

Because cooperation reductions apply within an already wide statutory range, the difference between good and poor cooperation can be a significant proportion of the penalty amount, quite apart from the underlying tax.

Poor cooperation also tends to extend the enquiry, which increases the interest running on the unpaid tax in the meantime, so slow engagement costs you twice.

Growth plan clients have free tax investigation insurance included, which supports professional representation to make sure cooperation is presented in the way HMRC's guidance rewards — see /fees for details.

Don't confuse agreeing with everything HMRC says with cooperating. You can cooperate fully on facts and access while still disputing HMRC's interpretation of behaviour or the tax figure.

Don't wait until the very end of the enquiry to hand over records. HMRC assesses cooperation throughout, not just at the final calculation stage.

Don't go silent because you're anxious about what the records show. Non-engagement almost always produces a worse outcome than early, organised disclosure.