What Boris Johnson has just done while trying to become Prime Minister of the UK.
Imagine you want to live in Dave's house. To get it, you walk in and openly do a
massive shit in his front room. Dave moves out. Thing is, your shit smells so bad you decide
you don't want it after all, leaving the house and the rest of
the street for that matter, a desolate rancid mess.
This is known as doing "a Boris".