[Revised July 2011. See also 'English Jewish surnames revisited', March 2012.]
My late father had a special interest in Jewish history and a very positive attitude towards Jews - unlike his brother who was in this regard something of an 'evil twin' whose belief in an international Jewish conspiracy was unshakable.
My paternal grandparents and great-grandparents were either Roman Catholics or members of the Church of England and there was no suggestion of any awareness of Jewish ancestry. But, oddly, virtually all my father's friends were either Jewish (surnames: Pittman, Babel, Mossenson ...) or had surnames which are often indicative of Jewish ancestry (Miller, Bloomfield, Rees ...).
Even his barber was Jewish (of German origin) and, when Dad retired due to ill health, the hairdresser (whose shop was near his office) gave him a card with a touching note in which he referred to himself as my father's "devoted Freund."
I never talked to my father about these matters as I only began to take an interest in them after his death. Was he aware of the possibility of Jewish ancestry? I doubt it. Did his Jewish friends suspect that his family was Jewish or part Jewish? This is possible. In an early photograph my rather anti-Semitic uncle bears an uncanny resemblance to Franz Kafka!
In fact there are some surnames in my family tree - mainly on my father's side - which could indicate Jewish origins. Beck, Fisher and Langman seem the most likely.
English names have been adopted by Jewish immigrants over the centuries. The migrations of the 19th and 20th centuries are well known. Earlier waves of Jewish immigration are less well documented. Many descendants of Sephardi Jews from the Iberian peninsula settled in the British Isles in the 16th and 17th centuries and gradually assimilated into the Christian mainstream.
Some names are more likely than others to be associated with the possibility of Sephardi or other Jewish origins. Amongst the names of my forebears I am looking at in this regard - apart from the names mentioned above - are Davis, Lester, Harris, Michell, and also English, Pember, Russell, Sturgeon and Ward.