BT, Vodafone and Verizon Wireless are amongst the leading companies giving UK spy agency GCHQ unlimited access to their network of undersea fibre optic cables, reports The Guardian.
They are passing on details of their customers' phone calls, email messages and social networking entries to GCHQ, new documents leaked by the whistleblower Edward Snowden show.
The undersea cables in question help form the backbone of the Internet and carry traffic from people around the world, so giving GCHQ free access also potentially affects the data owned by non-UK citizens.
GCHQ is able to tap the cables and store huge volumes of data for up to 30 days for further analysis. It uses special software systems that can detect key terms to help it pinpoint bits of data of interest.
A document seen by a German newspaper confirms that telecoms companies involved in the spying have been given codenames to help conceal their identities and protect them from public criticism.
The companies involved include BT, Verizon Business, Vodafone Cable, Global Crossing, Level 3, Viatel, and Interoute. Several of these refused to comment on their involvement to The Guardian, but noted they were obliged to comply with UK and EU law.
The UK government has always been able to request access to the national telecoms infrastructure on behalf of the security agencies, and the operating licenses of the telecoms companies spell this out.
What has made it easier however is the deployment of fibre cables, with digital telecommunications now even easier to hack into when required.
GCHQ's listening station in Bude, north Cornwall plays a lead role in the operation and the The Guardian recently reported that the US National Security Agency had even helped fund its operation, to enable it to share the data collected.
Image Credit: Flickr (Defence Images)