There has been a surge in the number of British Jews applying for Portuguese citizenship following the vote to leave the European Union.
Around 300 Jews have submitted applications in the six weeks since the referendum result, compared to five in the whole of last year.
Descendants of Sephardim who were forced to convert or leave the country in the 16th century have been able to apply to become a Portuguese national since January 2015.
Dr Michael Rothwell, who represents the 200-strong Jewish community in Porto, said: "We expect interest from more British communities throughout the rest of the year.
"There has been a concerted interest from Britain. It was not 300 isolated individuals; it was groups of Jews from a few communities, and Jews in other communities will likely think about the opportunity."
Dr Rothwell, a Manchester-born maths teacher, explained that the applicants, most of whom live in London, were in all likelihood "taking advantage of the possibility of Portuguese nationality to retain their European citizenship.
"I would not expect many to actually move to Portugal. Jews in many countries feel insecure and would seriously consider moving, but at the moment this is not the case with British Jews."
If they did decide to emigrate, he said British Jews would find "a country which now has the opposite attitude to Jews to the one it had 500 years ago.
"At the moment, we believe Portugal is the friendliest country in Europe for Jews."
As a result of research into the mass forced conversions of the 1500s, Dr Rothwell said that "a large percentage are aware they have Jewish ancestry, so people have a favourable outlook towards Jews".
He added: "If any British Sephardim are thinking of coming to Porto, they will find themselves very welcome, in both Porto and Portugal generally."