The UK must redouble its efforts to "wipe out anti-Semitism", Home Secretary Theresa May said Sunday.
According to the BBC, May said she "never thought I'd see the day when members of the Jewish community" would be fear staying in Britain.
She was spoke at a service in London in memory of the victims in the terror attacks in France this month, including four people who were murdered in a kosher supermarket.
Police say there is "heightened concern" about risks to Jewish people.
The president of the Board of Deputies of British Jews, Vivian Wineman, welcomed the home secretary's speech, saying Jews in the UK should be alert to the terror threat but not alarmed.
May said the attack on the supermarket in France was "a chilling reminder of anti-Semitism, not just in France but the recent anti-Semitic prejudice that we sadly have seen in this country."
"I know that many Jewish people in this country are feeling vulnerable and fearful and you're saying that you're anxious for your families, for your children and yourselves," she continued.
"I never thought I would see the day when members of the Jewish community in the United Kingdom would say they were fearful of remaining here in the United Kingdom."
"And that means we must all redouble our efforts to wipe out anti-Semitism here in the United Kingdom," she said.
The UK's threat level remains severe, which means a terrorist attack is highly likely. The Met has increased its patrols in areas with large Jewish communities.
On Friday Met Police assistant commissioner Mark Rowley, the national policing lead for counter-terrorism, said a security review was being carried out in the UK in the aftermath of the attacks in France.
He said police were holding talks over "more patrols in key areas" following concern from the Jewish community and after "anti-Semitic rhetoric from extremists" in France and elsewhere.
Speaking after Sunday's service, organized by the Board of Deputies of British Jews, Wineman welcomed the decision to increase police protection for the Jewish community.
He said: "Of course there is a real terrorist threat. People shouldn't be alarmed, they should be alert but not alarmed. There is a threat but don't exaggerate it."
When asked if British Jews were moving to Israel because of the terror threat, he said there had always been a steady stream going and they went for positive reasons to express their Jewish identity.
He said that the British Jewish community was "very happy here" and that the "vast majority of British people were not anti-Semitic".