I peer down the alley, knowing the bottleneck leaves no room for manoeuvre. Clear. The sign ahead points towards the asylum, so I beckon my squadmates. As we dart down the path, a scream peals out from ahead and as we reach what we hoped was safety, we instead find undead terror. Welcome to London, site of the zombie apocalypse.

Or perhaps it's not London – it could be Glasgow, Sheffield or another city where Slingshot's live gaming event 2.8 Hours Later is held (dates and locations at 2.8hourslater.com). Channelling the likes of video game Left 4 Dead, teams are sent out into real-world streets on a mission to obtain clean water. Survival requires dodging or distracting zombies, working out strategies, and "hacking" waypoints to access co-ordinates.

As if caught in some parallel reality, you'll play out your quest among an unaware general population, the game's route taking you through eerily quiet or disused areas, and the occasional shopping centre. With key scenes played out by actors, 2.8 Hours Later manages to deliver an immersive story. A general level of fitness is required as there's lots of running, but the survivors' after-party almost makes up for having to engage in actual exercise.

The experience will depend greatly on your team-mates, however. Book with friends who are into the theatrics and it could be fantastic; unfortunately, I was paired with lads on a stag-do, which somewhat lessened the impact. Playing in the darker months is advised for maximum atmospheric effect, but testing your gaming skills in the flesh is a thrill regardless.