Four men have been arrested by police investigating sexual abuse allegations among the Orthodox Jewish community in north London.
Home affairs correspondent Danny Shaw said the BBC understood Rabbi Chaim Halpern, 54, had been arrested on suspicion of sexual assault.
The rabbi, who runs a synagogue in Golders Green, is also being questioned on suspicion of perverting justice.
The BBC has learned Rabbi Halpern was one of four men arrested on Wednesday.
Three men, aged 25, 62 and 64, are also being questioned on suspicion of perverting the course of justice.
In December, in response to claims that he had acted inappropriately towards women, Rabbi Halpern issued a statement denying any wrongdoing.
He said: "I proclaim I am innocent of all allegations."