"BT lost me as a revenue generating customer when I called them after many overseas calls and asked how I could bar international calls due to the nuisance, as I don't get personal calls from outside of the UK. The Droid I spoke to claimed it would be illegal to do so, and had no words when I pointed to the illegality of the calls under Privacy in Comms regulations AND asked why spoofing CLI data wasn't held to be a breach of BT's T&C (and thus allowing for a block legally) he just couldn't answer those points. My view is BT like the termination revenue they get for this."
BT and other UK telcos must handle calls in a non-discriminatory way. They're obliged to make an attempt to terminate the call. Most international calls don't arrive on BT's network - they'll use a switch like Arbinet's in London, get passed over to a UK telco and eventually be handed to BT, if the terminating line is one that BT handles. BT only know the preceding link in the chain - not the originating network or caller. There's no way to confirm the validity of the CLI. There's no telco equivalent of a MAC address.
Biting the hand that feeds IT
