There were apparently none before 1066, they came with the Normans.
At first things went well for Jews in England, but the Crusades whipped up antisemitic sentiments, including pogroms (massacres) in London and in York. In 1290 Edward evicted all Jews from the realm. Most were allowed to take only what possessions they could carry. Population figures at that time are unknown, but are estimated at probably a few hundred, and no more than a few thousand.
Nearly all evidence that there had ever even been a Jewish presence in England was eradicated. While some refugees from the Spanish Inquisition (so-called Marranos) may have fled to England in secret after their expulsion from Spain in 1492, officially Jews were not allowed back into England until permission was granted by Oliver Cromwell in 1655.
So, for a large portion of the Middle Ages, there were NO Jews living in England.
Me, Jewish cultural historian