Exactly 20 years ago, in the first three months of 1993, more than 30 men in the care of Her Majesty's Prison Glenochil were on heroin, sharing needles and syringes.

A prison-wide HIV testing campaign revealed 12 of the men had become HIV positive as a result.

Twenty years on, HIV treatment has radically improved the health and longevity of people with the virus. For anyone receiving an HIV diagnosis in the early 1990s, however, prognosis was poor and society less than accepting, especially of men infected through sharing needles in prison.

When the report of the outbreak warned of the risk of spread from the so-called Glenochil 12, the report's authors were unaware just how prophetic their words were of what was in fact a human tragedy.

In one case at least, the infection of a partner would trigger the first trial in the UK of someone for HIV for "reckless and culpable behaviour". In 2001, the High Court found Stephen Kelly guilty and returned him to the custody of the prison service in whose care he had contracted the virus in the first place. Implications for him, his partner and family were disastrous, and created a knock-on effect among people with HIV.

A string of other stories was related in a tabloid newspaper a few years later, naming individuals and their closest connections, while also feeling entitled to breach intimate details of the men and their families.

This first report globally of an HIV outbreak in a prison in Scotland created a stir. Even with the well-known high rates of injecting among the young men and women of the housing estates on the edges of Scotland's biggest cities, it was headline news.

Drug education measures for drug users in prison had been insufficient to protect the Glenochil 12. A subsequent inquiry by the Scottish Affairs Committee of the House of Commons concluded that anything between 22 and 43 inmates might have been infected, while another 258 were missed from the study having been released or moved to another prison within the study period.

Outside prison, by contrast, a raft of measures including needle exchanges had started to turn around an epidemic of HIV infection that had peaked in 1986, six years previously.

Day to day, the majority of drug users in communities would have made use of these harm-reduction measures. Once behind prison gates, however, inmates addicted to heroin found a different set of rules.

In a rapid response, prison authorities introduced counselling on admission, detox and rehab, and sterilising tablets to clean syringes and needles. Syringes and needles themselves, however, were excluded. They still are.

The official report at the time recommended "urgent measures" to prevent further spread among prison injectors. Experience in the community was clear. Harm minimisation through provision of needle exchanges, substitution treatment with methadone, support on release and good links with community and health agencies would mirror strategies in the community from which prisoners came. For those 12 men infected in Glenochil in 1993, time in prison had taken them right back to experience the same conditions that had fed the epidemic a decade before.

Now, 20 years on, what has changed? Pressures have increased with soaring occupancy, and yet advances have been made. Provision of clean needles and syringes, however, remains taboo to Scottish prisons.

Proposals to a pilot needle exchange in 2009 were met with threats of a walk-out by the Scottish Prisons Officers' Association. Scottish Government policy stated in its Hepatitis C Action Plan (2006) remains in the red zone. In response to SPOA concerns for its members, the SPS undertook a thorough study and concluded: "It is important that, where possible, inmates of prisons have access to the same services in prison that they would have if they were living in the community."

It was also found that needle exchange schemes in 46 prisons in four other European nations had reduced rates of HIV and the Hepatitis C Virus (HCV). Despite safety fears expressed by Scotland's prison officers, no single instance of use of needles as weapons had been recorded.

Where these schemes have stopped, it has been been due not to opposition from staff, but to political interference. Indeed, whereas 85% of staff in a European study had opposed introduction of the schemes, 100% wanted them kept when politicians closed them, a remarkable change based on direct staff experience.

As long ago as 2001, a review of the HIV strategy in Scotland received evidence from the then SPS Medical Adviser on HIV prevention and concluded: "We recommend that the SPS considers whether it can do more to reduce the potential for HIV transmission in prison."

SPS standards currently support an enlightened approach to drug use in prison. Harm reduction is integral, taking the form of substitute prescribing, harm-reduction packs, condoms, lubricant and dental dams. In some prisons, there is even a needle replacement scheme at reception and the offer of sterile injecting equipment on release.

The one gap is in provision of clean needles and syringes during custody itself, and it seems that the whole project is off the agenda.

It might be argued that not only are needle exchange schemes unacceptable to prison officers, they are no longer necessary due to the success of other existing educational and harm-reduction measures in prisons.

This latter point was scrutinised by the same researcher and her team which reported on the original Glenochil outbreak. This time, the primary focus was on Hepatitis C, not HIV. This study, published in the latter part of 2012 found that the rate of illicit injecting drug use and of the Hep C virus (HCV) in injectors in Scotland's 14 prisons is the lowest in the literature. This is due in great part to drug treatment in Scottish prisons, including harm reduction.

It found, however, a 3% incidence of HCV in the prisons during the period of their study. The researchers conclude that although the risk and rate of exposures to Hepatitis C during current imprisonment was low, risk accumulates the longer someone is in prison.

Scotland has an internationally recognised reputation for its pragmatic drug policy in tackling HIV. This has not stalled in our prisons. Local NHS boards now provide prison medical services. NHS Forth Valley, where Glenochil is situated, hosts the largest number of prison establishments of any NHS board area and is an example of a positive change in the relationship between prisoners' health and prison.

There is a renewed opportunity to revisit a pilot of prison-based needle exchange schemes in a less threatening context.

The majority (64%) of people entering prison have used drugs in the previous 12 months, and many (39%) worry that drug use will be problematic on their release. Based on all of the evidence, policy and the real risk of exposure and infection, Scottish prisons must introduce needle exchange schemes to complete its strong harm-reduction approach. It is long overdue, two decades after the notorious Glenochil outbreak.

Roy Kilpatrick is the former chief executive of HIV Scotland and blogs at http://scotfreehiv.tumblr.com