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. )
