The statistic that around three quarters of prisoners smoke has been used to demonstrate the scale of the problem.

It means prison officers and other staff are routinely exposed to second hand smoke in their daily working lives. The figure also means a quarter of prisoners don’t smoke. These inmates are not only deprived of liberty, but also forced to share a cell, a workshop or a recreation area with someone who smokes - potentially for months or years of their life.

The SPS say they have not had law suits yet from prisoners alleging their rights are breached by such a situation, but it is surely only a matter of time. Unions have raised concerns on behalf of staff - understandably. We know more and more about the risks of second hand smoke and hardly anyone now has to put up with it in their workplace.

Resistance to a ban in prisons has largely come from issues of internal order. With so little to cheer their daily lives, will some prisoners become harder to handle if deprived of cigarettes?

Those high rates of smoking are part of the picture too. Most prisoners come from poorer communities where smoking is more prevalent. Arguments about depriving people of their only pleasure must count double behind bars.

But smoking exacerbates the health inequalities that the Scottish Government aims to reduce. If tobacco is a way of life, that can be changed, says SPS chief executive Colin McConnell, who also claims that while smoking rates are high among prisoners so is the desire to quit. The SPS now believes any hostility to a ban can be addressed, follow a similar model to New Zealand’s successful ban. Urgent discussions on introducing e-cigarettes are taking place. These are seen as hugely less risky, and widely accepted in public places outside society.

There is definitely a risk that cigarettes will become another contraband item in jails. They are already used as currency to an extent. But the prison service is used to managing the drugs problem. It could be that once the ban is fully enacted, prisoners will be prosecuted for breaking the law as would anyone who breaches it on the outside - with fines for those convicted. In practice, small drug seizures in jail are often not dealt with through the courts, despite the illegality of possession. Instead, the ‘orderly room’ discipline system is used, with breaches punished by the loss of privileges, such as television, use of the prison ‘canteen’ or denial of recreation time. Similar punishments might apply for smoking.

The views of prisoners are not yet clear - surveyed results have not yet been published. Prison staff are said to have mixed views.

One hope the prison service is not harbouring is that this will deter those who would commit crime. While enforced nicotine withdrawal in prison might be put off some offenders, Mr McConnell is not confident. “The people who make their way into prison tend not to think through the consequences of their behaviour. For many when they arrive at prison and are told they can’t smoke it will be a shock to the system and we need to make sure we are ready to respond to that,” he says.