I worked in Brixton prison for five years as part of the Education Department. As a teacher you occupy an odd position, because you experience the place differently - it hardly needs to be said - from a prisoner, yet don't have the same relationship to prisoners as the uniformed staff (who at their worst can be extremely obstructive). One of the creepier government suggestions is that teachers should wear uniforms, a truly horrendous notion which would destroy the relationships teachers try to build with prisoners.

Much has changed since early 1997 when I left. Nationally, the prison population has continued to grow (it's now well over 60,000); cuts have slashed the Department where I worked; and there is a different Governor, reputed to be less liberal than the one I knew.

Brixton is mainly (about two thirds) remand prisoners - that is people awaiting trial but unable to get bail for whatever reason (60% of remand prisoners nationally are released after trial). Convicted prisoners were all on shortish sentences (maximum four years), apart from a special unit which contains serious sex offenders who have to attend a "sex offenders treatment programme" (SOTP) before they can apply for parole.

The "regime" was generally fairly relaxed, at least compared to other London prisons. There was a push to have prisoners out of their cells twelve hours a day. Before, men were often banged up for as much as twenty three, in cramped, dirty "peters", filled with the stench of shit, the windows tiny and barred. The plan was to offer activities, including classes, to men to fill the day, but it didn't always work.

Lots of prisoners, remand and convicted, are provided with work in the jail; work is paid (the best-paid was in the kitchen - about £12.50 a week). Some don't want to work, for whatever reason, others are denied it. I was meant to have a prisoner paid to work with me on the prison magazine; in practice it was murder to find someone who could pass through the various hoops before permission was granted (anyone with a drugs-related charge, convicted or not, could forget it). Other jobs include cleaning floors and, if you're very lucky, library duties.

Still, a terribly long time is spent locked in a small cell about the size of a box bedroom. With current overcrowding, I doubt if anyone has a cell to themselves; at its worst there have been three men to a cell. There are no TVs in cells (partly due to an argument about licences), so entertainment is restricted during the long hours between around 8pm and 8am to playing cards and reading, or listening to the radio.

Normally each wing opened its confusingly-named "canteen" (a small shop) once a week, for men to buy cigarettes or tobacco, sweets, tea, and so on. Remand prisoners were allowed "spends" sent in form outside; convicted prisoners had a ceiling of £10 a week. Most prisoners stink of Golden Virginia because it's cheaper to buy than a packet of fags.

There used to be a rota for the showers: men couldn't wash every day. I think this has now been changed.

About a year before I left, "Rule 43" was abolished, so vulnerable prisoners (including, but not only, sex offenders) were integrated into the rest of the population. At that time, this seemed to be largely working, but as the population increases I'm sure it has proved more difficult to manage. I'm not talking here about the special wing, where men have committed appalling offences (one once assured me nobody had ever proved he "had sex with the corpse": he was trying to freak me out, and it worked).

Brixton is not, or was not, a particularly violent prison; others (and even more so Young Offenders Institutions) have worse reputations. Even so, alarm bells were a regular event. When an alarm sounds, as a civilian you have to stand by the wall as dozens of uniformed officers charge past, heading for the emergency, and others busily lock men up. Sometimes a fight has broken out between prisoners, occasionally an officer is involved. Prisoners are often overpowered and dragged to the "block" (the punishment, segregation wing). To this day, bells in shops (supermarket cashiers summoning assistance, say) make me very uneasy.

Even for an outsider who could go home at night, the prison was a profoundly depressing place, with what I can only call an "aura" which hit you the moment you walked through the gates. My job was interesting, but sometimes it took an enormous effort of will simply to go into the place.

It is no surprise to me that there continue to be alarming numbers of suicides - including, sometimes, of men who need not expect to be there very long. It is simply so frightening that even three weeks seems like a time they cannot endure. Precisely what is frightening is hard to define, for as I say there is relatively little violence (I'm sure more took place than I knew about, but still not the popular image). But the sense of a loss of freedom, a sense you pick up on even if you've got keys, hits you hard.