The investigation has found that private intelligence companies are able to rent access from mobile phone operators and this can then be exploited to allow the tracking of the physical location of users across the world. They are also potentially able to intercept calls and other private data, including bank accounts and emails.

These intrusions, which are very widely exploited, rely on commands designed to help phone operators track their customers’ whereabouts. Such commands, known as “signals”, are sent via a kind of global switchboard for the telecoms industry called SS7.