No immigration hasn't caused it, though the way that's been managed has added fuel to the fascists fire.
It's happening because the arseholes want it to happen, and are choosing to make it happen, because fascist uprising is a 40 year cycle in the UK and we're literally due it.
It's being massively fueled by those who want to try and turn it into something usable for themselves, destabilize a government that several power bases don't want, and followed by lots of dumb semi disenfranchised fools.
They are the same lot that make everyone's lives hell in school, make living in SH miserable, destroy community gardens and everything we try to build for kids in the community, and pissed up trash everything they can on a Saturday night, battle with the bouncers, security and the police, turn up primed to fight at footie, start road rage crap if they feel dissed, and routinely batter the women dim enough to show interest and have kids with them.
They are always like this, just looking for a new 'reason' to do what they always do.
They are the bane of LC and WC communities, and the minority.
It's a hot summer and violence begets violence so if the police can't sort it, we're headed for an excuse for looting and other groups of brainless violent men to go for who owns the streets and delivering street justice.
There was a London riot and looting against immigrants in the 1600's, they hung a fair few before people started worrying about would feed their women and kids, - it did the trick for a bit.