The same as Wellington in NZ, London is liberal (although they weren't in the last election) the heartland are Tories.
The overall demographics of people that are voting to leave were older people and conservatives. The guardian said it best, they said something like what right do we have to give the next generation a future that they don't want.
I'm sick of conservatives the world over, the baby boomers are just trying to hang on to power as long as they can and screw everyone but themselves. Truly the most selfish generation.