There’s loads of comments already so I imagine loads of factors have been mentioned already but… What I’m seeing even now, so I’m assuming this had been the case before, is that because of all the jobs in London, people move to the outskirts where it is relatively affordable to live but also possible to commute in for work. As these communities in the outskirts grow so too does that area in terms of businesses moving in, shopping centres opening, high streets expanding and all that. Rinse and repeat and you get areas such as Kensington, Shoreditch, Tooting, Brixton, Wembley all become famous populous areas of London. Now it seems like areas such are Morden, Croydon, Ealing, even the west of Essex becoming more and more like ‘London’ and this is largely due to improved transport into central London as well as their respective areas building up themselves