There is a lot of anti-Israel opinion in Britain and some people are clearly anti-Semitic.
I recall in the 1960s and 1970s some occasional anti-Semitic comments among the working class people with whom I lived and was brought up – but it was almost exclusively to do with ethnic stereo-typing about meanness, and was much less vociferous than anti-Black or anti-Irish comments.
Now I live in an area with among the largest Jewish populations in Britain, and I live in social housing among working class people. The local Labour MP is Jewish, and so in fact was his Conservative opponent in the last election. In the three years I have been here I have never heard any anti-Jewish comments by working class people. I have however heard a lot of anti-Asian comment (little distinction being made between Muslims or Hindus) and hostility towards South Asians is the dominant form of racial hostility I would think. (Afro-Caribbean people have largely been accepted, although there is some occasional retrograde hostility.)
If you read the comments in The Guardian you will find a lot of educated middle class hostility to Israel, but I think that a lot of effort is made by the vast majority of such commentators not to attack Jews as such. There is no discussion of Judaism as a religion, since most Brits aren’t interested in religion and are not “Christian”. They are not even post-Christian for the most part. They are post-post Christian. [There is btw vastly less inhibition about attacking Catholicism and Catholics in general.]
The hostility in my opinion has little to do with the historic tropes of anti-Semitism – i.e. racial opinion, supercessionist theology, nor ethnic stereotyping.
For the most part, except for Asians, Britain is a live and let live country as far as most of the population is concerned. Actual incidents of anti-Semitic actions almost all seem to be done by a very small portion of some Mulsim communities.
So I think what you call anti-Semitism is all about anti-Israel feeling. Many people are equally hostile to the United States. And there is much much more hostility and hatred of Islam and Muslims.
