Is it proper to display a Union Jack flag (which is made up of the cross of St. George and the cross of St. Andrew) in an orthodox Synagogue. My Synagogue intend displaying this together with the Israeli flag. I would appreciate your comments and any halachic reasons if these exist. Thank you

Rav Moshe Feinstein [IM OC 1:46] wrote that even though he does not recommend placing flags in the shule he sees no breach of any halacha to do so or daven in a shule with flags. Since the flag of England is not an avodah zara artifact but rather a national symbol, it should not be different to the American flag rav Moshe is discussing in his responsum.