I think it means this:
A company located in a different country providing a telecoms service to people within the UK, and that telecoms service includes, email, instant chat, webmail, peer to peer, basically anything! - then various methods can be used to issue the warrant for interception, perhaps email for example.
It gives the government the power to monitor any form of communication either in the country or where traffic is coming in or out of the country. It's as far reaching as it gets.
Biting the hand that feeds IT
