Around half of Scottish inmates are illiterate, according to official figures which have prompted calls for an overhaul of prison education.
Major deficiencies still appear to blight the standard of learning in prisons, despite improvements in recent years.
Justice Secretary Kenny MacAskill revealed in a parliamentary answer that 50 per cent of male inmates attending learning centres had a literacy level at or below Intermediate 1 level.
He released figures from the Scottish Prison Service, which also showed that 64 per cent of women at the learning centre in Cornton Vale Prison, on the outskirts of Stirling, were deemed at or below that level. The same applied for 46 per cent of young male offenders at the learning centre in Polmont Young Offenders Institution, near Falkirk.
Interim chief executive Willie Pretswell advised Mr MacAskill that anyone at or below Intermediate 1 was considered to be "lacking functional literacy".
The figures led Labour justice spokesman Richard Baker to demand that inmates spend less time playing video games and more on reading and other skills.
Mr Baker, who submitted the parliamentary question that led to Mr MacAskill's response, also called for the recommendations of his party's Literacy Commission to be enacted as soon as possible. These included wider use of synthetic phonics, testing to identify problems at an early age and continuing professional development so that teachers could drive up standards.
A soon-to-be-published HMIE inspection is expected to show that prisons are hampered in tackling literacy, by the absence of common strategies to identify prisoners' skills.
A wide range of projects and initiatives in prisons has proven highly effective in encouraging inmates to improve their literacy skills, but there were not enough opportunities to do so within other activities.
While facilities for learning were impressive, the inspection is also expected to show that prison staff did not make enough use of ICT, online learning and specialist resources which would have helped inmates. It is understood, too, that staff did not do enough to help inmates continue learning after release or transfer to another prison.
Meanwhile, an adult learning expert in England and Wales has highlighted the poor educational attainment of prisoners. Tom Schuller, associate director of the National Institute of Adult Continuing Education and co- author of Learning Through Life, noted that, in addition to their poor reading skills, 30 per cent had been regular truants from school and nearly half had no qualifications
Mr Schuller, a former head of continuing education at Edinburgh University, argued that it made economic sense to have better-educated inmates, since it cost at least pound;40,000 a year to keep one person in prison.
Analysis by NIACE had found that even a 2 per cent reduction in recidivism would produce a saving of pound;130 million.
Writing in our TES sister paper in England, Mr Schuller called for "very thorough" diagnostic assessment when offenders arrived in prison, in order to pick up on past educational failure.
It is not just prisons who have to wrestle with inadequate readers. A debate on literacy in the Scottish Parliament last week heard that further education colleges were having to take remedial action to improve literacy and numeracy among student entrants - even those on journalism courses.
Anne Douglas, chair of the Scottish Union Learning board, last week recalled the Literacy Commission's finding that up to one million adults in Scotland had difficulty with reading, as she highlighted the absence of a Scottish Government strategy on "workplace literacy". She called for central funding to ensure consistent provision throughout the country.