Haim Korsia, France's Chief Rabbi, acknowledged this week that it was "always a possibility" that some of the estimated 35,000 French Jews living in Britain would return in the wake of the Brexit vote.

Visiting London, he said: "It is always a possibility that someone will go back, because if he forgets his roots, that is very dangerous. But I think the French Jews in Britain want to build a part of Europe here, and they were very surprised by the Brexit vote".

Rabbi Korsia, a passionate French nationalist, was in Britain this week to support the Le Tsedaka charity.

One of the French Jewish leaders taking part in Tuesday's day-long conference at the residence of the ambassador, Sylvie Bermann, had described an incident in central London, in the wake of the vote.

Rabbi Korsia said: "This man had lived and worked here for 18 years and he was walking in Piccadilly with a friend, speaking French and smoking a cigarette. Suddenly a man ran up to them, punched this man in the shoulder, and said: 'I have been following you and the smoke is intoxicating me. I don't want your sort of people to do that in my country, this is my country, not yours."

It was the first time such an incident had occurred, the French Jewish victim said.

Nevertheless, Rabbi Korsia was optimistic and said he and his office hoped they would be "a bridge" between France and the UK Jewish community. He said they were "very important" and were not "an expatriate community".

Rabbi Korsia maintained that those French Jews in the UK had not come to Britain because of antisemitism. Instead, he said, they had come for work opportunities - "the decisive factor" - and he believed they currently paid less tax in the UK than they might in France.

He had not heard any feedback from French Jews in the UK that they might consider leaving in the wake of the Brexit vote, but repeated his belief that all the diaspora French Jewish communities - in the UK, in Canada, in Israel - were effectively part of the whole French essence of society.

Earlier, Rabbi Korsia utterly rejected the claim of Jewish Agency leader Natan Sharansky that there was no future for Jews in France.

Rabbi Korsia said that the essence of France was its freedom, and that it was precisely that freedom of which Sharansky had dreamed during his years in prison in the Soviet Union.

Rabbi Korsia, who served in the French armed forces, is a strong proponent of French-Jewish identity and has had many meetings with President Francois Hollande and Prime Minister Manuel Valls discussing how best to strengthen French Jewry's position in society.

It was a mark of their commitment, he said, that they had given "more than 100 million euros" to help fight terrorism and protect the Jewish community in France.

On Monday, Mr Sharansky spoke in Paris at a Jewish Agency event. He said: "There is no future for the Jews in France because of the Arabs, and because of a very anti-Israel position in society, where new antisemitism and ancient antisemitism converge".

But Rabbi Korsia brushed those remarks aside, and similar comments made by Israeli prime minister Benjamin Netanyahu, after terror attacks in France.

He understood, he said, that they would say these things because of their positions, but "Jews are part of France. Prime Minister Valls says France without Jews is not France, and France is part of freedom".