Grethe Thomson, a psychologist with the city council, said that remarkable results had been achieved since 1999 when the project was tested with small groups of non-readers in four primaries. Learning support teachers taught groups of five for 45 minutes a day over eight weeks.

Ms Thomson said: “The results were highly significant with pupils in the experimental schools making 8.6 months’ progress in reading and 7.5 months’ progress in spelling over the eight weeks intervention period. In other words, the average progress was one month in one week.”

Of eight non-readers, who were below age five on the British Ability Scale, seven made a minimum of seven months’ progress.

Subsequent phases included older pupils but the same results appeared with an average of eight months’ progress in eight weeks for reading and writing. The most recent phase lasted only five weeks and evidence shows this is not long enough for pupils to make progress.

Ms Thomson said that the remediation programme made the link from sounds to symbols. “It starts from what is familiar, the sounds in words and links it to what is unfamiliar - letter symbols.”

Teachers believe the approach boosts children’s confidence and encourages them to persevere.

English speakers take two and a half times longer than learners of most other languages to achieve the basic elements of literacy, according to another international study.

“The sound to letter correspondence is more complex in English than in most other languages. English is an alphabetic writing system and requires the pupil to develop the alphabetic principle - that units of print map on to units of sound. For this to happen, pupils need to develop phonemic awareness,” Ms Thomson said.