You've gor me really interested now Dot.
This site tells you about the Aliens Acts of 1905, 1914 & 1919.
http://www.20thcenturylondon.org.uk/server.php ?show=conInformationRecord.35 It is very obvious that most immigrants remained Aliens - only a certain percentage applied to become naturalized. I suppose the majority didn't want to cut their ties with "the old country" of their birth - or perhaps didn't have the necessary requirementts to be accepted for naturalization. There was an agreement with Russia in 1917 to return some aliens back to Russia to serve in the army during the first World War after the assassination of Tsar Nicholas. They were given the choice of serving in the British Army or being returned to Russia. They were also allowed to plead their case for remaining here without going in the army. You may therefore find some army record of Julius or more likely Barnet having joined up.