"I'm learning a new living here." How bikes are helping ex offenders start afresh and rebuild their lives.

In the XO Bikes workshop deep within Pentonville Prison, North London, four trainee mechanics are checking the frame alignment on a secondhand Trek bike. They are using the old-school string technique, which they've spent the morning mastering, under the tutelage of course leader and former prison officer Paul Nurden.

Test complete, they move on to reseating and truing the wheels, while enthusiastically explaining the skills they're learning and how they plan to use them on the outside. John, who has just received a parole hearing date, is already a trained vehicle mechanic and has been helping Nurden deliver the courses. (To protect their identities, we're not using real names or giving surnames for John and the other inmates in this feature. )

He's hoping the judge will be impressed by the positive way he has used his time. Next to him is Ali, who was a cab driver prior to going inside - a job he can't return to once he gets out.

"I'm learning a new living here," he beams. The classroom is calm and quiet, in complete contrast to scenes I soon witness elsewhere in the prison. Even as a very brief visitor, 'The Ville', a Victorian-era institution, is an intimidating place, full of movement, noise and tension.

It's dinnertime, and some cell doors are open, revealing tiny rooms, each with basic bunk beds and a toilet. This Category-B/C prison, built in 1842, was designed to hold 520 men in single-occupancy cells. Now there are over 1,100 inmates here, mostly two to a cell. We're greeted with some hard stares as we pass through multiple metal gates, but many prisoners are eager to talk, especially to the man I'm with: Stef Jones from XO Bikes.

Easily identifiable in his branded top, Jones is known as "Bike Geezer" in here, and word has spread that the mechanic course XO offers inmates can facilitate more than just temporary respite from the heavy atmosphere of the wings - it can open an escape route from a life of crime and incarceration.

Sadly, statistics state that many of these men, after being released, will end up back inside. According to a report released in February by former MP and Secretary of State for Justice, David Gauke, over half (56.9%) of men released from prison after serving a short custodial sentence will reoffend.

Britain's jails are full to bursting, and four out of every five inmates are repeat offenders. XO stands for ex-offender, and XO Bikes exists to help break this bleak cycle. "Our mission is to provide people the skills and self-belief they need to make it on the outside," Jones tells me as we walk the floors of Europe's biggest jail wing.

"Many of these guys have never been given recognition for anything in their entire lives. Simply getting a certificate saying they've completed the course, let alone passed it, means a massive amount to them. "

While volunteering in HMP Brixton, as a mentor in the chaplaincy, Jones grew exasperated at seeing men coming back in, months after walking out the door full of good intentions. Their stories were depressingly similar: no one would employ them.

"When you can't get a job it's hard to get your life into any sort of order," Jones explains. "And it's all too easy to fall back into bad company and habits. " Jones's solution was to employ them himself. He founded a charity called Onwards and Upwards, and during the Covid lockdown conceived the idea of XO Bikes. The programme takes offenders through Velotech training courses, with the bronze level currently being taught in Pentonville and Feltham Young Offenders Institute.

More advanced courses are delivered at XO Bikes's South London training centre. Once they are qualified bike mechanics, ex-offenders are helped by the charity to find employment. XO Bikes keeps a staff of 'fixers', as graduates of the course are known, and takes in pre-loved bikes - some donated by the public, others arriving via the Metropolitan Police (recovered but unclaimed) and Transport for London (abandoned at stations) - which are refurbished and sold at their stores in Wandsworth and Lewisham.

"We take bikes with a past and blokes with a past," says Jones, "and we give them both a chance to have a future. " In a previous life, Jones did 20 years as an advertising executive, and he still knows exactly how to grab people by the eyeballs.

When donated bikes arrive badly scratched, the frame is resprayed and it becomes an XO 'swag' bike. Each one of these restored steeds is sold with a bike lock shaped like a set of handcuffs. Everyone who completes the programme gets a number, starting with Tray, XO1, who has now been working as a mechanic for three years and helps Nigel Brook, XO's head mechanic, deliver advanced courses.

Each 'swag' bike is branded with a code, the fixer's digits followed by the number of bikes he has restored (e. g. 'swag' bike 001/020 is the 20th bike Tray refurbished). There's also a QR code that links to more information about the person who worked on your bike. For the purchaser, it's part of a cool story, but for the fixers these elements are badges of honour, reinforcing a real sense of achievement.

And the stats speak for themselves: almost 100 men have been through the programme, and just four have re-offended. Recently, to raise awareness, Jones began collaborating with Nic Georgiou, a Strava artist, who designed a cycling route around London, taking in the city's four main men's prisons (Pentonville, Brixton, Wandsworth and Wormwood Scrubs), while digitally etching the XO logo on the map.

After a chance meeting with Georgiou, I find myself part of the crew tasked with riding this route, along with XO Bikes programme-graduate-turned-employee Ollie (XO22) and several members of the Chain Gang, a London-based cycling club.

We meet in the Breakout Café, opposite Pentonville, where Ollie presents us with XO-branded striped cycling jerseys, designed to resemble the prison clobber you see convicts wearing in cartoons. When dawn reluctantly breaks, the day is as grey as the prison walls, against which we form a line-up for a photo, before pedalling into the drizzle.

Joining us for the first few miles is Will Norman, London's Cycling and Walking Commissioner, an effervescent ambassador for human-powered transport and passionate supporter of XO Bikes. "The XO programme is really reducing reoffending rates, but also, at the other end, they're making high-quality bikes available to people at a really affordable price," Norman enthuses, as we roll through backstreets. "For people on low incomes, the high cost of bikes is a huge barrier to cycling, so this is a great initiative. "

As a case in point, I'm riding a good-as-new-looking carbon-framed Trek Madone, which arrived in the XO system via the Met and will be sold on to some lucky punter at a fraction of its original price. The first part of our ride is fiddly, as Georgiou navigates us through narrow alleys and up and down cul-de-sacs, expertly drawing digital lines that will, once uploaded, magically manifest the shape of a road bike on the side of a gigantic XO logo.

"It's more art than exercise," observes Norman wryly as we pause our GPS devices again before U-turning and reactivating them, to create the outline of the handlebars. Norman has meetings to attend and bike lanes to plan, so he soon scoots off and our pace picks up, as we start the less intricate part of the drawing, crossing the river and joining the dots between HMP Brixton and Wandsworth.

Ollie tells me his story while we ride. He'd enjoyed a good education and a settled upbringing but made a mistake in his 20s that resulted in a conviction, and soon discovered doors were shutting in his face.

"I couldn't get a job anywhere," he explains. He found out about XO Bikes, completed the course, and is now operations manager at Jones's charity Onwards and Upwards, bringing firsthand knowledge of the challenges people with criminal records face. Our shared physical challenge soon goes up several cogs too, as the temperature plummets and we're hit by relentless rain and hail storms.

A tyre problem puts paid to Chain Gang rider Darren's day, and when nightfall begins nipping at our heels, Louis leaves us too, suffering severe toe numbness. Ollie, Nic and I grit our chattering teeth and circle around to Wormwood Scrubs, finally finishing the XO logo by 9pm, after a full day in the saddle and 127km of riding.

The next day, returning the bike to XO's Wandsworth store, I meet 23-year-old Danny, who is servicing a fork in the workshop. He tells me he had always ridden and built bikes as a kid, but got in with the wrong crowd as a teenager, and ended up in trouble with the law.

After being put in touch with XO Bikes by the Forward Trust, he completed the course, as Fixer X010, and now works in the shop five days a week. "It feels good to have a job," he smiles. "My family is proud. " And with some stability in his life, he can look forward, and make plans. "I'd love to have a bike shop and a business of my own one day," he says, sounding a lot like a bloke with a future.

How to buy a bike from XO

For years, savvy cyclists have been saving significant sums on new bikes by taking advantage of the cycle-to-work scheme. Now, a similar concept has been developed for people purchasing pre-loved steeds from XO Bikes. Just launched, and intended to improve access to good bikes for more people, the Recycle to Work scheme enables you to buy secondhand bikes through your employer, reducing the tax burden. Completely refurbished bikes bought from XO Bikes already cost about half their original price, and this scheme means you can make additional savings of 30 to 50%. For more, see xobikes.com/recycle-to-work-scheme.