It's the real thing - almost - as we battle to save London

London has fallen. Society has broken down. The Chimera -an alien race that wants to kill all people -have ravaged the city and only a few humans survive.

This was the scenario I found myself in at a PlayStation 3 event under Waterloo Station arches. The video-gaming company collaborated with immersive theatre group Punchdrunk to promote its new game, Resistance 3, by creating a real-life survival horror game with London at its centre.

Groups of nine at a time were led through a door under the station arches into a dark warren of rooms. Our mission: to send a vital message to Resistance 3 hero Joseph Capelli to aid his operation in the USA and defeat the killer aliens.

We had to navigate through a disorientating and terrifying series of rooms to enter a code into a computer, avoiding Chimeras hellbent on ripping us apart.

The experience required cooperation with fellow players. The high-tension environment binds the team together. Thankfully, my group made it out alive.

The four-day event, which ends on Sunday, sold out within minutes.

Claire Lefevre, a 20-year-old dance student from Highbury, said: "I liked being in a group... I'd have been too scared to go in alone. It definitely felt like I was in a video game."

Graphic designer Katie Lowry, 35, from Stoke Newington, agreed. "I was terrified. It felt like being in a horror film."