Police were called to a strictly Orthodox holiday camp in Kent last month after the appearance of a stranger aroused suspicion.
A bareheaded man, not wearing Orthodox dress, entered the marquee which served as the camp's temporary synagogue at Kent University, Canterbury, one evening.
According to Levi Yitzchok Schapiro, a Jewish community activist from Stamford Hill, north London, when the man was approached, "he said his mother was Jewish. He took out an Arab hat and said that this was his Jewish hat".
Asked by the rabbi to show further proof that he was Jewish, "the man said his mother lit candles every Monday night. The rabbi asked him to leave the camp".
When the man was later spotted still around, police were called but he had vanished by the time they arrived.
The following day police returned after the stranger reappeared, talking to a group of 11 and 12-year-old children. According to Mr Schapiro, the man had told them he had been sent by his brother, who, he claimed, was a leader of a local mosque.
Kent Police said that officers arriving on the scene on August 22 had spoken to the man. "No offences were committed and the man left voluntarily," a police spokesman said.
Mr Schapiro said the incident had been "scary" at first but "the police co-operated with us really well and everyone felt safe afterwards".