Inmates could soon be banned from smoking at prisons in England and Wales, the UK's Ministry of Justice has said.
A pilot scheme, which will monitor how prisoners react to the move, is being planned by the UK government, but sites have not yet been chosen.
A spokesman for the Ministry of Justice said: "We are considering banning smoking across the prison estate and as part of this are looking at possible sites as early adopters."
The pilot scheme is expected to launch in the spring of next year and, if successful, the ban would be rolled out across all prisons within 12 months.
There are fears that the ban could cause disruption in prisons, with around 80% of inmates in England and Wales believed to smoke, according to the NHS.
Smokers will be offered nicotine patches as a substitute.
Steve Gillan, general secretary of the Prison Officers' Association, told The Times that introducing the ban would be difficult.
"There is no pretending otherwise," he said. "It could cause disturbances, but they have done it successfully in Canada and in young offender institutions in England and Wales.
"We welcome this move. It is our policy to have smoke-free prisons for our members.
"We will work with the ministry to make sure it works effectively."
Mr Gillan said that without a smoking ban the prison service risked legal action from a non-smoker claiming to suffer from the effects of passive smoking.
A document sent to senior prison staff and seen by The Times said: "You will no doubt be aware that the decision has been made that the time is right for the prison estate to adopt a tobacco and smoke-free policy to provide a smoke-free workplace/environment for our staff and prisoners."
It went on to say that the prisons involved in the pilot scheme would be selected from the southwest.
The smoking ban introduced in England in 2007 restricted smoking in prisons, but allowed inmates to light up in their cells.