Is antisemitism normalised in the UK?

In a clip from an interview posted by Sky News on Tuesday 24th March, Dr Dave Rich, Director of Policy at the Community Security Trust described public expression of anti-Jewish conspiracy theories and stereotypes as growing in the UK, saying:

"There always used to be quite a strong taboo against expressing anti-Jewish racism ...
I think nowadays more and more people are saying it out loud. Because, for whatever reason,
it’s a more permissive environment or the taboo has changed or social media is a place
where you can just say anything, as horrible as you like, and get away with that.
So, it’s like those protections are broken down as well."

That prompted Sky’s Niall Paterson to ask whether antisemitism in the UK has become normalised. Dr Rich replied:

"I think it is becoming that way. The strange thing about it, the irony about it,
is that we know from loads of opinion polling that most people in Britain don’t feel this way.
All the opinion polling shows us, across the population as a whole, this is actually one of the least antisemitic countries there is,
and yet the public expression of anti-Jewish prejudice and stereotypes and conspiracy theories,
is much more common than it used to be."