The canadians have also opted for a combined service, known as the Canadian Security Intelligence Service (CSIS)
or, (as with most things Canadian) it is also known as Service canadien
du renseignement de sécurité (SCRS) - Canada having a strong french
connection.
For our American Friends, the CIA and the American intelligence community has a large web presence.
For our British Friends, the British Secret Service, also called the British Secret Intelligence Service (SIS) or MI6. Basically their spy network.
The British 'homeland security' network is the British equivalent of ASIO, being The Security Service, or MI5. If you wish to pass information relating to an internal threat in Britain, use them.