ICAEW: The Revenue has been forced to delay sending its £100 penalty notices from February until the end of April, due to the added resource burden caused by Brexit
Individuals who failed to submit their self-assessments by 31 January will still be fined £100 despite receiving the penalty notice months later.
Full story: https://economia.icaew.com/news/february-2019/hmrc-delays-penalty-notices-due-to-brexit