CH29560 | Data gathering: Penalties: Inaccuracy penalties
From HM Revenue & Customs · Compliance Handbook
A person is liable to an inaccuracy penalty, not exceeding £3,000, if they provide inaccurate data in response to a data-holder notice, and
the inaccuracy is due to either the data-holder’s failure to take reasonable care, or their deliberate behaviour
the data-holder knows of the inaccuracy at the time when they provide the data but do not inform us at that time, or
the data-holder discovers the inaccuracy after the data has been provided but fails to take reasonable steps to inform us.
FA11/SCH23/PARA32