Chief Rabbi Ephraim Mirvis has joined faith leaders in condemning a crackdown on Christmas by some Muslim countries.
Brunei has threatened to imprison anyone for up to five years who celebrates the Christian festival in public.
Authorities on the island, in south-east Asia, warned that the ban will be strictly enforced.
Chief Rabbi Mirvis, said faith communities “have a responsibility to stand together to oppose discrimination”.
He said: “The shocking ban on public celebrations of Christmas in Brunei is reflective of an intolerance that, as Jews, we simply cannot countenance.”
Brunei’s leader, Sultan Hassanal Bolkiah, announced earlier in the year that the country would begin to implement a hardline interpretation of Sharia law, with punishments including death by stoning or amputations.
Authorities could also hand out $20,000 fines for any religious ceremony contrary to Sharia, including singing religious songs, sending festive greetings or putting up Christmas trees, crosses or candles.
However the ban does not apply to the Sultan's luxury Dorchester hotel chain, with branches in Los Angeles, London, and Paris.