SolvedCH64300 | Penalties for Failure to File on Time: How to process a penalty: Enforcement of penalties
From HM Revenue & Customs · Compliance Handbook
The penalty for failing to file on time must be paid within 30 days. The 30-day period begins on the date the penalty assessment is issued.
A penalty assessment
may be enforced as if it were an assessment of tax,
is treated, for procedural purposes, in the same way as an assessment of tax except where there are specific rules for penalty assessments, such as time limits, see CH64200, and
may be combined with an assessment of tax.
A person does not have to pay the penalty before an appeal against the assessment of the penalty can be considered, see CH64520.