There maybe some skirmishes here and there, from the right wing under the guise of Brexit, but it will soon die away. Its the reaction of the bulk of tory leave voters and the 40 odd percent of traditional labour leave voters that will be key. These groups are unlikely to take to the streets, but will, once they have found their new strength in opposition to the EU, organise themselves in voting blocks to effect normal elections and will try to fight tooth and nail against any perceived new EU rules which they feel are being forced on them. One target would be to force situations where HM Government gets in to difficulty in implementing EU laws and ultimately is hauled up before ECJ. How disrupting this will be is hard to assess, initially for maybe a year or more it will be more or less guerrilla warfare in British politics, but eventually it will fade away as long as the EU itself reforms and demonstrates to the despondent leavers that all they are doing now is cutting their noses off to spite their face. There will also have to be a big upsurge in EU assistance for improving Youth Employment across the EU, otherwise the Youth who wanted to remain, will start to think maybe their grandparents were right after all.
Brexit in my opinion will not happen, article 50 will not be delayed but cancelled, then everyone except our current crop of disgraced leading politicians will have a second chance, including those in the EU, to make things right. Lets hope that having come so close to the perfect storm, that the lights in Europe will go on again and everybody get a fair share.