No it isn't
There's a dedicated artificial town for training purposes used by all the UK services.

I tried to find the name of it, but when I put "dedicated riot town" into Google, the first result was "Brixton".
( Grrrmachine the indifference engine, Tue 9 Aug 2011, 5:51, archived)

I tried not to laugh at this, because I wasn't sure if it was meant to be funny, but I couldn't help it.

( BraynDedd Natasha Kaplinsky's labia majora, Tue 9 Aug 2011, 7:45, archived)

Oh cool, is it as big as London?

( mike woz ere 7442200 & 7696970 getter, Tue 9 Aug 2011, 12:44, archived)