An interesting thread BD... I was going to go off on an anti-gated community post.... but then I read this;

http://www.wmin.ac.uk/page-2903

I would have said that gated communities are a dreadful phenomenon (based on the American model), and that this type of 'fortressing' may give a short-lived feeling of security to the paranoid inhabitants, but there are seriously bad consequences for communities and social cohesion, with the exclusion of (less fortunate?) members of society.

But the above paper suggests that the issue is more complex, and that it may be beneficial to maintain the overall social mix of an area, rather than having people move out of an area because they don't feel safe (and therefore move an area further toward social / economic segregation).

Perhaps London is a special case, in that we tend to have more socially and economically mixed areas anyway. In the US, I believe the situation is more extreme.