I am happy to declare myself a supporter of authority. I am a great admirer of people who dedicate their lives to upholding the power and obligations of the state in terms of criminal justice, from Home Secretaries to gaolers and from judges to police officers. But equally, I am a natural sceptic and perfectly willing to believe that the state makes errors. In the case of one man I met while researching this section, the errors were multiple and egregious. His story raised an important, uncomfortable question. What is prison for?

Ben Gunn is a former inmate at Shepton Mallet prison, which was the oldest in Britain when it closed in 2013. He served nearly half a lifetime behind bars. He was not an innocent man. The crime that sent him to jail was murder, the worst a person can commit, but that, in the end, doesn’t seem to have been the principal reason for keeping him banged up – most convicted murderers serve less time than he did. No, his ‘error’ was that he didn’t fit into the prison system. What a fantastic paradox, that because he didn’t fit into the system he was forced to remain within it for more than thirty years.

It was to understand something of that ‘system’ that I had gone to Shepton Mallet. What is it like for those who, by wickedness, foolishness or sheer bad luck, end up inside? What does it feel like when that cell door bangs closed and you are left with nothing but the bare physical essentials and endless tracts of time in which to reflect on the actions that brought you there? Prisons have been around for as long as human beings have lived in organized societies, under agreed codes of law and behaviour. Shepton Mallet’s lifespan as a working prison covers hundreds of years and its history illuminates our changing attitudes to crime and punishment.

I didn’t feel entirely comfortable about entering Shepton’s forbidding precincts, for reasons I explain in the chapter, but my reluctance was as nothing compared to Ben’s. His first words to me were: ‘It’s not a happy place.’ And during the few hours he spent back behind the walls that had deprived him of liberty and meaningful life for so long, he often struggled to contain his emotions and fear.

From everything he told me it seems he took his punishment on the chin. He also made the most of his time, gaining two degrees. But he has struggled to see a wider purpose for incarceration. ‘You can’t have punishment and rehabilitation simultaneously,’ he told me. ‘You can’t punch someone in the mouth and give them a Band-Aid.’ As for deterrence, Shepton Mallet has its own cautionary tale. The Kray twins, two of the most notorious characters in British criminal history, served time there when it was a military ‘glasshouse’. They were young at the time, they still had the chance to turn their lives around. Instead, prison seems to have attached rocket boosters to their nascent criminality. It is Ben’s opinion that, in the end, the prison system is not about prisoners at all, but rather ‘for making everybody else feel better’.

In my broadcasting career I have conducted a lot of interviews with remarkable people but I rate this encounter at Shepton Mallet as the most compelling and thought-provoking. Nevertheless, it was a relief to get prison out of my hair and travel north to Manchester to meet a body of people for whom my respect is boundless. These are the men and women of the fire service, whose role is to rescue us from fire, car crashes, natural disasters and the like – to rush towards danger as everyone else runs away. The response of the fire brigade to the terrible conflagration at Grenfell Tower in west London in June 2017 was a reminder, if any were needed, of the bravery and commitment of this rare breed of public servant.

My plan was to tell the story of these Manchester firefighters through the station in which they served. What I hadn’t bargained on was the scale and ambition of that building, which is situated in London Road near Manchester Piccadilly railway station. Its design, in fact, is similar to Shepton Mallet prison, for they share a striking feature. Each, for contrasting reasons, is a kind of citadel, built around a central courtyard and presenting high walls to the world. It was from here that appliances rattled out, bells clanging, to douse the flames of incendiary bombs dropped by the Luftwaffe in the Second World War. Thirty Manchester firemen were killed in the war and it was intensely moving to be shown a fire-damaged relic of one of the worst infernos, in which two men from the London Road station lost their lives.

People have been dousing fires for even longer than they have been locking each other up in prisons. But fighting fires occurred on an ad hoc basis and well into the Middle Ages it was not unusual for entire towns of timber-framed buildings to be razed by fire, with no organized body responsible for, or equal to, fire prevention on such a scale. This situation began to change following the Great Fire of London in 1666 and the first municipal fire brigade in Britain was founded in Edinburgh in 1824. The London Road Fire Station, which closed in 1986, offered a glorious window into the evolution of firefighting in the twentieth century and represented, down to its very design, an Edwardian ideal of service to the community.

For what I hadn’t realized, until I started my investigations there, was that London Road was a residential station. Not only did the firefighters work alongside each other on dangerous call-outs but they lived, literally, on top of each other. It was a real pleasure to meet men who had grown up here and listen to them reminiscing so enthusiastically about their childhoods within those high walls. It was, effectively, a giant adventure playground – the biggest dare of all being to climb 100 feet to the top of the hose tower when all the crews were out and they had forgotten to lock the tower door.

It was a place very much of Manchester, right in the heart of the city, yet apart from it by virtue of the enclosing walls. It wasn’t until I talked to a firefighter who had attended the Moss Side Riots of 1981, that I fully understood this relationship with the community. He had been astonished to see bricks being hurled at his appliance as he and his colleagues attempted to contain the fire and damage around them. It was a reminder that a firefighter must remain apart and impartial, whatever the circumstances or provocation.

The firefighters of the London Road station stood side by side, in work and play. It was an honour to stand with them, however briefly. It may seem like a small point but it was also instructive to wear the uniform and to operate a fire hose, feel the colossal physical power of it and understand the seriousness of its purpose. The tools of my trade are laptop, pen and paper. However fraught a day I am having, I am not expected to save the lives of others and risk mine in the process.