Last summer, we posted about the Guardian’s revelation that authorities with the UK Government Communications Headquarters (GCHQ) weeks earlier had entered the outlet’s building and overseen the destruction of hard drives containing documents leaked by former NSA contractor Edward Snowden.

In a new video released Friday by The Guardian for the first time, several of its employees can be seen using power tools to destroy the hardware on July 20, 2013, under what The Guardian called the “watchful gaze of two technicians” from the GCHQ.

The outlet recounts some of the incident in more detail in this post at its website:

Three Guardian staff members – Johnson, executive director Sheila Fitzsimons and computer expert David Blishen – carried out the demolition of the Guardian’s hard drives. It was hot, sweaty work. On the instructions of GCHQ, the trio bought angle-grinders, dremels – a drill with a revolving bit – and masks. The spy agency provided one piece of hi-tech equipment, a “degausser”, which destroys magnetic fields, and erases data. It took three hours to smash up the computers. The journalists then fed the pieces into the degausser.

Two GCHQ technical experts – “Ian” and “Chris” – recorded the process on their iPhones. Afterwards they headed back to GCHQ’s doughnut-shaped HQ in Cheltenham carrying presents for family members, bought on their rare visit to the capital.

“It was purely a symbolic act,” Johnson said. “We knew that. GCHQ knew that. And the government knew that,” He added: “It was the most surreal event I have witnessed in British journalism.”

Guardian editor Alan Rusbridger previously recounted that he’d tried to explain to government authorities that destroying the files would not stop the reporting on the story.  Already, other collaborating media organizations were reporting on the NSA stories from other countries, and continue to do so today.

The Guardian’s release of the video also comes just ahead of the release of a new book – The Snowden Files: The Inside Story of the World’s Most Wanted Man – written by the Guardian correspondent, Luke Harding.