I’ve splashed out on BT openzone on the basis of a recommendation from someone. For £5.00 a month I get 500 minutes of wi-fi access. The coverage (at least in London) seems quite comprehensive.

Downside:
It creates a pressure to work all the time - there is no unproductive labour here - particularly in terms of checking email

Upside:
I find it useful to be able to access my email constantly - it means while I’m travelling around or stuck in a hotel I can get some work done instead of having a huge backlog of stuff when I get home.