My strange night in a sensory deprivation tank

Hidden below St George’s Wharf in Vauxhall, down the road from a now defunct gay sauna, is Floatworks, a wellness centre that offers ‘floatation therapy’.

Sensory deprivation tanks can be found in most British cities — in bohemian towns like Bristol and Brighton, but also in Birmingham and Belfast. The concept is simple enough: people are locked in an unlit pod and lie there with nothing but their thoughts. Some people report hallucinations, others a deep sense of calm. Wally Funk, the 82-year-old who was blasted into low earth orbit last month aboard Jeff Bezos’s private rocket, endured ten hours of sensory deprivation when she trained as an astronaut.

Ten hours seemed a dangerously long time, so instead I booked a measly 60-minutesession and cycled over after work. The tank looked like a windowless prototype for a self-driving hatchback. ‘You’ve got your earplugs and your Vaseline,’ said the attendant, gesturing towards a bamboo bowl that held a little sachet of ‘white petrolatum’. No other explanation was provided. My mind darted back to the gay sauna.

Kit off. The promotional photos showed floaters wearing swimming costumes, but the online community insists that birthday suit is the only appropriate dress code (which makes a sort of sense, given how foetal the set-up feels). There’s something quietly disconcerting about the mix of whale music pumped into the pod and the vaguely medical scent of the floatation solution, made up of, among other things, half a ton of Epsom salts.

The liquid was just over a foot deep and heated to what I assume is body temperature. It’s also toxic. Hanging on one of the hydraulic arms was a bottle of water to spray my face in case any of the fluid went near my mouth or eyes. With the lid shut and only an electric blue light for company, it became obvious what the Vaseline was for: the various nicks and grazes that one naturally acquires as a Spectator journalist began to itch ferociously. Never mind, there’s no turning back now. Out went the light and slowly, too, did The Best of Brian Eno.

The chamber was just large enough to stretch out my arms and legs, which is just as well. Moving my limbs was about the only entertainment. Occasionally a shimmer of something passed across my eyes. Hallucinations, but nothing revelatory. Then, from beneath me, I heard a low rumble. Just the muffled clattering of the Victoria line. Once I recognised it, it proved a comforting sound.

All of a sudden, the ambient music started up again. I was sure it had only been a couple of minutes. The thought that someone might barge into the little room and discover me zonked and starkers was enough to reanimate my slippery limbs. I hopped out. Exactly 60 minutes. I emerged with a feeling of almost artificial serenity, as if someone had dialled down the radio in my brain. I returned into the Vauxhall evening, to join my fellow earthlings.