Jeff is in London and ran into a port blocking experience, something I have also experienced in New Jersey last year.
My feeling is if your paying xx pounds a day for High Speed Internet, you should have high speed Internet, not just access to the Web or Email.
For my trips to Europe the last two years I actually decided which hotels to stay in based on who the Internet provider was, and actually called and checked in advance. On tip is to find out if you can get a public IP address versus a blocked IP. That has enabled me to use softphones, CallVantage, Broadvoice and Vonage in the UK and France.