A survey carried out for the Association of Teachers and Lecturers claims that less able pupils are not benefiting from the hour in the school day dedicated specifically to improving reading and writing skills.

The survey, based on questionnaires answered by 340 primary teachers, found that 80% believed the literacy hour was not helping pupils with special educational needs.

Peter Smith says the government should not introduce the literacy strategy "on the cheap"

Children who were particularly gifted were also believed not to be benefiting from the introduction of the literacy hour, an element of the national literacy strategy which, while not compulsory, is strongly encouraged by the government.

There were also mixed responses about teachers' confidence in their own ability to teach the literacy hour. Only 55% of the survey's sample felt "professionally skilled" to teach it, 38% said that they lacked training and 75% said support from their local authority was inadequate.

The survey, conducted for the union by the Opinion Research Business, also found that teachers felt over-burdened by the extra administration that the literacy hour had created.

Paperwork to support it was described as "unmanageable" by 74% of the teachers, with 46% claiming that the hour of specialist teaching required four hours of preparation.

In publishing the survey the ATL reiterates earlier findings that teachers are spending their own money to buy books and other resources.

"Ministers say the literacy hour is fully funded. Our survey shows it is not. The government can't innovate on the cheap," said the ATL's General Secretary, Peter Smith.

"What jumps off the pages of the research is the concern of those who teach children with special needs. The literacy hour must be made to work for those who need it most. There is an equal question about whether above-average children are being stretched enough."