Have Britain and Australia recently confiscated guns? If they have, then one could make a case that the confiscation might well have led to the increased crime. If not, one would be hard put to make this case. One might argue, as well, that the increased availability of, or willingness to use, guns in London, not confiscation, is responsible for increased crime. I note that the article said violence with the use of knives has also increased markedly, so it doesn't appear that gun ownership, or lack thereof, is the signficant factor.


As far as allowing immigrants to retain their own culture, again, if this were a recent phenomenon and coincided with an increase in crime, you could argue for the connection between the two. Otherwise, where would the connection be?


One has to be careful in defining "crime" too. I remember when I was living in New York people were shocked when, during a police strike, crime went down. Well, of course it went down, there were no police available to make any arrests. The point is that increases or decreases in crime might also have to do with increased or decreased vigilance on the part of authorities.