You can split the 'Jacks' into three:
a) those, nationalists who are consumed with disrespect for any humans that aren't just like them, and convinced by extreme right-wing politics that all of their issues will be solved by removing 'foregners from their view.
b) those, who have genuinely had a rough deal since the 2009 recession and feel that they have been left behind. The nationalist politicians seemed to answer their prayer as it promised so much.
c) those, who similar to the second group have also had a rough time but rather than following the baying mob, actually listend to the arguments from both sides of the debate and decided that the situation they knew wasn't necessarily responsible for their personal predicament.
So come the day (if it does) when the UK walks into a chaotic no-deal situation, those groups
will have a rude awakening. How they behave may well become a major problem. Those in group c) may well take to the street as supply chains fail and prices start to rise steeply. Some of those in group b) will realise that they have been duped and seek some sort of revenge on those who lied to them; and hardcore leavers in group a) will probably suddenly adopt as low a profile as possible to avoid being physically attacked. I imagine some of that dissappearing act will start as soon as it becomes clear that we will crash out of all the existing arrangements. A few might continue to try and blame everybody else for the failure of their 'solution', (when the corrupt 'project fear' statement becomes completely toxic), but they will only do that via the anonymity of social media logins.