Using tactics that included luring diplomats into fake internet cafes, The Guardian reports that British intelligence spied on major world leaders during the 2009 G20 summit in London. The revelation is based on documents provided by whistleblower Edward Snowden, who fueled earlier leaks about the Government Communications Headquarters (GCHQ) and the US National Security Agency (NSA) through The Guardian and The Washington Post.

The G20 summit in London included President Obama as well as 20 other heads of state and governing bodies. During the summit, the GCHQ reportedly monitored the foreign politicians' computers and phone calls, and had direct permission to do so from high-level officials in then-PM Gordon Brown's administration.

GCHQ wanted an edge in negotiations

The intent of the alleged spying was to gain an edge in negotiations against other countries, including Turkey and South Africa, according to The Guardian. The GCHQ managed to tap into phones and computers by establishing internet cafes with built-in key logging and email intercepting software, as well as by hacking delegates' BlackBerrys to monitor messages and phone calls. The British intelligence agency was apparently able to read the attendees' emails even before the attendees themselves accessed them.

The key logging reportedly may also have provided the GCHQ with online login details — such as usernames and passwords — that were used by foreign leaders. The NSA, which shares information with the GCHQ, was allegedly gathering information during the summit as well, attempting to intercept and decrypt phone calls made by then-President Dmitry Medvedev. The GCHQ is said to be involved with the US PRISM program as well.

The operation was 'very successful'

By the time the G20 delegates' financial leaders met in London five months later for a separate meeting, the GCHQ had apparently improved the surveillance technology enough to create a live map of telephone activity, which it projected onto a large wall in one of its offices, reports The Guardian. The leaked documents note that the effort was "very successful" in allowing them to see delegates' activity. This program is said to have only run for six months, though it's unclear if a newer technology has replaced it. Britain will be hosting heads of state once again for the G8 summit tomorrow.

Update: BlackBerry tells us that there is no secret backdoor into its devices and that it stands by the security of its software. The company's full statement is below.

While we cannot comment on media reports regarding alleged government surveillance of telecommunications traffic, we remain confident in the superiority of BlackBerry's mobile security platform for customers using our integrated device and enterprise server technology. Our public statements and principles have long underscored that there is no "backdoor" pipeline to that platform. Our customers can rest assured that BlackBerry mobile security remains the best available solution to protect their mobile communications.