About 80 prisons are said to be using the scheme

The project was launched with money from a book of letters between a retired farmer and a man serving life for murder.

The farmer, 77-year-old Christopher Morgan, from Sussex, set up a trust with the proceeds from The Invisible Crying Tree, a record of his correspondence with prisoner Tom Shannon.

The money funded self-help manuals using Toe by Toe, a system devised by a primary school teacher, now retired: Keda Cowling.

"It's a very structured system, so anyone who can read can teach with it," Mr Morgan said.

Spreading the word

He got permission to try it in Wandsworth Prison in London where it had a faltering start until taken up by one of the prison officers, Neil Lodge, who got some of the prisoners to help him.

"Within 18 months they had taught 80 people to read, and had only five dropouts."

Mr Morgan said that - naively - they thought they would be able to take it around the country.

That proved difficult until they got the support of the Prison Officers Association.

"Since then there's been no stopping it."

About 80 establishments in England and Wales had taken it up, he said, and he had also been invited to Scotland and Northern Ireland.

As a result, Mr Morgan has been awarded the Longford prize - named after prison reformer Lord Longford, who died in 2001.

He intends using his speech at the award ceremony in London on Monday to appeal to the prison service hierarchy to back the project.

"We are only scratching the surface," he said - having reached perhaps 1,000 of the 30,000 or so prisoners who cannot read and write.

The scheme fits with the observations of one of the more celebrated prisoners of recent years, Jeffrey Archer.

Lord Archer suggested politicians consider compelling prisoners to pass reading and writing tests before they were released from jail.

He said it could help deal with the causes of crime - and result in thousands of prisoners being returned to society without the stigma of total illiteracy.