Rural Northamptonshire is perhaps best known for its cobblers. Want a decent pair of brogues? This is the place to come. But there’s another, slightly more modern industry around here. Because this part of the world, on the north-eastern fringe of Motorsport Valley, is where almost a third of Formula One teams come for their engines. About a hundred 2.4-litre V8s emerge from Mercedes AMG High Performance Powertrains at Brixworth each year, on their way to new homes at McLaren, Force India and - obviously - Mercedes.

It’s not often they let journalists inside this place. Especially not when they’re developing an all-new, top-secret and somewhat-controversial V6 turbo to meet next season’s new regulations. Later they’ll show us one being tested, but for now we’re relieved of our cameraphones and shuffled into the boss’s office. Andy Cowell is in charge of about 400 staff here, from engineers to mathematicians and others with far bigger frontal lobes than your average Top Gear writer.

There are three parts to this place, he tells us: the bit that looks after this season’s engines, another bit that looks after next year’s, and a final bit that builds the battery packs for the Merc SLS electric supercar (using the same brainpower behind the KERS systems in F1). “We also work with about 30 companies within an hour of the factory,” he says. “Precision manufacturing firms and suppliers of highly specialist parts, from valve springs to aluminium pump parts.” Mostly, though, everything they need to make an F1 engine is all right here.

“All we’re really doing is finding the most efficient way to convert chemical energy trapped in fuel into shaft power,” Andy says. “And, next year, we must achieve a 30 per cent reduction in the fuel used in a GP.” To get some idea of how this is done, we must think small. Imagine the diameter of a pint glass, representing the cross-section of a human hair. Now imagine a dot in the middle, approximately the width of a peppercorn.It represents one micron. Scale all this down massively, and the measurements become minuscule. “If a piston heats up by one degree Celsius, it’ll expand by two microns,” says Andy. “So we need to engineer in miniature…”

Weirdly, the building in which this is done is huge. Light bounces off white floors like the corridors of a starship. Wires trail from machines like alien tentacles. This could be a room of supercomputers if it weren’t for the smell of hot metal in the air, as thousands of aluminium billets are cut to precise shapes inside big white boxes. Andy shows us an inlet finger follower, a little curved rocker that helps regulate a valve’s opening. It’s beautiful, and so polished it’s slippery, thanks to a diamond-like carbon coating that you’d usually associate with expensive jewellery.

“Once an engine goes down the pit lane in an F1 car, it’s effectively sealed for the rest of the weekend,” says Andy.

In other words, you can change a few settings, but you can’t get the spanners out. “Each driver gets eight per season, so it’s our job to make each one last. Engines must pass an exam before they leave here, which mimics everything from driving down the pit lane to a full-throttle straight.” Then, on a Sunday afternoon, there’s a team of people here in the Track Support room. They take data from the cars and play it back on an engine across the hallway. Mr Hamilton not happy in the first practice session? Just let the boys in the factory try a few tweaks before firing the new settings to the track.

After every batch of races, each engine comes back here and gets stripped down. Filings in the oil are analysed, using powerful microscopes and a team of measuring experts. Each engine component has a unique metallic signature, so every tiny fleck of metal in the used engine oil can be traced to the part from which it came. Too many piston shavings? Fetch the sandpaper! Of course, engines are supposed to wear. “It’s about how we manage the margin of failure,” says Andy. “A total failure should only happen in the factory after the race.”

It’s a balancing act between performance and reliability. How much do you stress it? How much do you protect it? Four litres of oil must lap the engine every two seconds. Its cylinders go through their cycle up to 18,000 times a minute, that’s 300 times per second. The 25kg KERS system - a box the size of a backpack - produces just under 1,000 volts. The electrons inside it move at the speed of light. Together, all of this makes somewhere around 750bhp… all squeezed down into a bundle of cylinders and exhaust pipes your average-sized bodybuilder could cradle in his arms.

We’re led into a room not unlike a recording studio, full of screens and knobs and buttons. Through a viewing window is the artist: 2014’s V6, spinning away on a dyno. We’re the first outsiders to see it. It’s obviously more compact than a V8, but not by much. It’s hard to tell, as it’s festooned with tubes and extraction fans. A huge pipe blows air into the engine’s snorkel intake, mimicking air speed, heat and humidity of any given circuit on any given day. Sometimes they run these bench tests 24/7 with up to three engines at once, while feeding energy from the dyno back into the building. The hot exhausts glimmer translucent orange like glow-worms.

It is, however, sealed away in its soundproof booth. So we’re led to another room where I’m handed some headphones, through which is played the sound of the V6 during a full lap simulation of a nameless circuit. And if anyone was worried about it sounding dull or turbo-whooshy, allow me to reassure you now: it’s emphatically still a Formula One car… albeit one with cleaner tones and a higher frequency than the current V8s, but still enough to make your eardrums flutter, especially when it yaps down through the new eight-speed gearbox.

Formula One? The future’s bright. The future’s British…

Words: Dan Read/Matt Jones

Photography: Justin Leighton

This feature was originally published in the May 2013 issue of Top Gear magazine