"The list, and many of the comments, dont make clear that there is are 2 kinds of "free" wifi: password-secured, and totally unsecured. There's a big difference. If you buy something using totally unsecured free wifi, your password and financial info could be available to people preying on unsecured wifi users.
The kind of wifi at St Pancras is totally unsecured- which is fine for general net surfing. But you definitely dont want to do internet banking while using that. And I personally wouldnt do any password-protected site, like email.
The other kind-- like in public libraries, or anywhere where you're required to "sign in" (either with a password you make up, or with a password the cafe staff will give you on a piece of paper), is the password protected free wifi. This is more suitable for email, facebook, etc. But even these places suggest that you dont use it for internet banking or for making any purchases.
It's irresponsible for Timeout not to note the difference between "free" wifi, and which kind is best for what kind of surfing."