The number of prisoners caught using drugs in Scottish jails rose to a seven-year high last year.
Official statistics show 1,133 inmates were disciplined for taking drugs in 2015-16, the equivalent of more than three a day. That compares to 1,003 the previous year and 634 in 2012-13.
Despite the increase in recent years, the 2015-16 figures are still below the 1,257 recorded in 2008-09.
The figures from the Scottish Prison Service (SPS) annual report were highlighted by the Scottish Conservatives.
The Tories are calling for the problem of drug-use in prisons to be tackled. The Conservatives pointed out that the figures would not include convicts who have taken drugs and managed to get away with it.
The party’s justice spokesman Douglas Ross MSP said: “This is an environment which is meant to be absolutely secure, yet it seems offenders are continuing their criminality within prison walls.
“The fact that more than three inmates are being caught using drugs every day shows there is a very significant problem, and these figures indicate it’s getting worse year after year.
Detecting and recording these incidents isn’t enough – it’s vital the Scottish Prison Service cracks down on this problem and makes sure these substances don’t keep slipping through the net.
“All political parties agree that rehabilitation of offenders is critical for society. But how can this be expected to take place while drug-taking remains so prevalent in prisons?”
An SPS spokeswoman said “robust” security measures are in place to prevent drugs entering jails and anyone found in possession of contraband is reported to the authorities.
She said: “Seventy-three per cent of prisoners tested on reception had illegal drugs in their system upon entry against 27 per cent on exit, demonstrating a reduction in prevalence of drug use of 46 per cent. SPS welcomes this significant reduction.
“Recovery is the explicit aim of all services providing treatment and rehabilitation for prisoners with drug problems. A range of substance misuse treatment and support services are provided, by adopting a multi-disciplinary approach.
“Significant investment continues to be made in the development of new technology and staff training to detect, deter and reduce the availability and supply of illegal drugs.”