[Symbiote]

A 10 year old PDF map [1] shows plenty of other fibre connections. Does everything really go through London?

Locating outside London would be a lot cheaper, for labour, land and power.

[1] http://www.globalcrossing.com/docs/fn/tanet-uk-map.pdf

[alicewales]

There is fibre outside London, but most of the main end-user ISPs have just the one POP and it's normally in Docklands. Everything ends up going through there one way or another.