I think some corners are louder and prouder, and with technology things are more visible, but I'm not sure if there are more racists/things are becoming more racist or that it's shown more. I think as others said that division in general has become louder, more blatantly supported by those who benefit from it, and a focus possibly than it was decades mast.
The original post is about getting more racist since previous decades ago, so not since Brexit - that vote was a little less than a decade ago - so are we talking since the early 00s, the 90s, 80s, 70s...
I think it would be very difficult to say Britain is more racist than the 60s when the Bristol Bus Boycott happened. Even the 80s with the race riots that happened then and a lot of shite going on then, I think that's difficult to say.
Also, the OP made foreigners equivalent to not White. There are many immigrants who are White or are regularly perceived as White who experience abuse. While not what most think of when discussing racism, the legal definition includes national origin, so yes, there are many white immigrant women who have personal experience on it.
In my experience - immigrated here over 20 years ago, visibly mixed race, obvious accent - I find I have less remarks and hostility about my ethnicity, it's a rarity for me, but I am getting more remarks and at times hostility on anything where...the best way I can put it is blending in or assimilated to what someone else perceives as British. My accent at times feels like it creates a target, that the content or politeness of what I say matter far less than how the other person feels about my accent, and I've noticed a shift in the last year or so where some people get agitated, I've started to hear "That's not a local accent!" or not a British accept and people asking how long I've been in the UK and getting unhappy I still have 'such a strong accent' or then getting less happy if I do anything else they perceive as not British enough. This had led to me getting less tolerant of people discussing my accent, it instantly brings up warning thoughts in my mind and makes me very uncomfortable, like how I can't be British enough is being poked at.
However, I bitterly resent what the left have done. It’s a question of scale. Mass immigration has been used to destroy our national identity and impose a new one on us. No one asked for it and no one voted for it.
As others mentioned, the "Boris Wave" and highest rates of immigration was under the Tories. It was the Tory Chancellor George Osbourne who called the immigration of the UK as "for-profit" in Parliament and brought in the 'private partners' among other ways corporations are making more money off of there being more immigrants coming in. That why even though the Tories brought in a lot of immigration law changes, most people - British born, naturalised British, immigrant, asylum seeker - see little benefit.
That they've somehow spun this to be something the left has done, when it's actually what those looking to squeeze 99% of us without a care for anyone but themselves is a masterclass in manipulation. Yes, people on the left are louder on defending immigration, that doesn't make them the cause.