The inaccuracy penalty system is intended to make penalties simpler to understand and more consistent across many taxes. HMRC has the power to significantly reduce the amount of penalties due. The largest reductions are for unprompted disclosures (as against prompted disclosures). The penalties also vary depending on the taxpayers’ behaviour. HMRC has 4 levels of behaviour ranging from taking reasonable care in dealing with errors to careless, deliberate or deliberate and concealed behaviour patterns.

There is no definition of taking reasonable care from a taxation standpoint. However, HMRC’s commentary in this area is helpful. HMRC accepts that 'reasonable care' cannot be identified without consideration of the particular person’s abilities and circumstances. HMRC recognises the wide range of abilities and circumstances of those persons completing returns or claims and accepts that what is necessary for each person to discharge that responsibility has to be viewed in the light of that person’s abilities and circumstances.

HMRC gives the example of not expecting the same level of knowledge or expertise from a self-employed, un-represented individual as we do from a large multinational company.