CH83060 | Penalties for inaccuracies: how to process the penalty: enforcement of penalties
From HM Revenue & Customs · Compliance Handbook
You must check the date from which these rules apply for the tax or duty you are dealing with. See CH81011 for full details.
A penalty for an inaccuracy / under-assessment must be paid within 30 days of the date on which the penalty assessment was issued.
Any assessment of these penalties
may be enforced in the same manner as an assessment to the underlying tax
shall be treated, for procedural purposes, in the same way as an assessment to the underlying tax, and
may be combined within an assessment to the underlying tax.
References to an assessment to tax, in relation to inheritance tax and stamp duty reserve tax, are to a determination.
FA07/SCH24/PARA13 (1A) (2) & (7)