For Jewish Downton Abbey fans, last Sunday's episode was a huge moment - the arrival of a character who is completely kosher. Finally.

True, there was excitement a couple of series ago when the Countess of Grantham's mother came to stay at Downton and we found out that her name was Martha Levinson.

But, as played by Shirley Maclaine, she did not start making blessings over those magnificent silver candlesticks they have on the dining table.Later it was revealed in, The Chronicles of Downton Abbey" a book written by Jessica Fellowes, niece of the show's creator Julian, that: "Martha's husband was Jewish, she herself is not, and their children were raised Episcopalians".

So the introduction of Atticus Aldridge was a breakthrough.

Lady Rose, the family black sheep who has already shocked her relatives after getting involved first with a married man and and then a black jazz singer, seemed at last to have found a suitable young man - handsome, well-mannered, cutglass accent. Someone who might even win the approval of the terrifying Dowager Countess.

But Mr Aldridge, played by Matt Barber, is not quite the perfect English gentlemen.

He is a member of a Ukrainian-Jewish family who fled to Britain after pogroms in Odessa.

But it is a family that has done very well. Aldridge is the son of the recently ennobled Lord and Lady Sinderby and is just about to take up work in the family bank.

Such aristocratic Jews fit well with the Downtown milieau and have history on their side too. After all, the Rothschilds (bankers like the Sinderbys) built so many country houses that a slice of Buckinghamshire became known as Rothschildshire.

But viewers should try to contain their excitement. Lady Rose does get through boyfriends very quickly so Atticus may not be around very long.