There's something very suspicious about this. Have anti-immigrant actions really increased since Brexit? Or is it that Leftists and Liberals are now focussing on actions which have occurred long before Brexit? In other words, it's the focus that's changed, not the number of attacks.
Think about it. Why should anti-Europeans start now, after they've been successful with Brexit – rather than before, when no one cared what they thought?
Is the Guardian saying that they were very few racist attacks before Brexit? Of course not... Well, I've never heard that paper say that before.
In other words, the rate of attacks hasn't changed, and the nature of actions hasn't changed. What has changed is that Leftists are milking these actions for political gain.