Josephine's letter is dated 21st March 2020. Children could have birthday parties on the 19th June 2020, albeit outside
Thanks for confirming that your post is entirely irrelevant given Johnson's indoor non-essential gathering, @Clavinova
Is Johnson really so slow of thinking that he was incapable of stopping at the door, saying "Sorry, chaps, this is illegal, thanks all the same but let's do it within the rules" and turning on his heel and walking away?