A few years ago, I perched on the edge of my bed in a tiny flat, breathing in a cloud of acetone fumes, using a scalpel to pick at the corner of an electronic travel card. More than 10 million Londoners use these Oyster cards to ride the city’s public transport network. I had decided to dissect mine. After letting the card sit in pink nail polish remover for a week, the plastic had softened enough that I could peel apart the layers. Buried inside was a tiny microchip attached to a fine copper wire: the radio frequency identification (RFID) chip.

My goal was to bury the chip under my skin, so that the machine barriers at the entrance to the Underground would fly open with a wave of my hand, as if I was some kind of technological wizard. But although I had the chip and an ex-Royal Marines medic willing to do the surgery, I failed to get my hands on the high-grade silicone I’d need to coat the chip to prevent my body reacting against it. Since then, people have used the technique I helped popularise to put liberated Oyster chips in bracelets, rings, magic wands, even fruit, but the prize for first London transport cyborg is still up for grabs.

The person who does will find themselves inducted into the community of “grinders” – hobbyists who modify their own body with technological improvements. Just as you might find petrol heads poring over an engine, or hackers tinkering away at software code, grinders dream up ways to tweak their own bodies. One of the most popular upgrades is to implant a microchip under the skin, usually in the soft webbing between the thumb and forefinger.