CH26640 | Information & Inspection Powers: Penalties: What is the penalty: Failure, obstruction, concealment etc: Initial penalty
From HM Revenue & Customs · Compliance Handbook
The initial penalty is a fixed amount of £300.
This is the first penalty you will assess, see CH26800, where a person
required by an information notice, or
that they have been notified are, or are likely to be, required by an information notice, see CH26260.
Operational guidance on the £300 penalty is at CH270100.
FA08/SCH36/PARA39
CEMA79/S118G