A new study has revealed that the education of thousands of children could be suffering because the acoustics in British schools are so poor that they cannot hear properly.
The sound reverberation, or echoes, in some classrooms have been found to be so bad that up to a quarter of consonant sounds are unintelligible. Yet there are no mandatory requirements relating to acoustics in classrooms.
In the first UK study of its kind, a Hampshire primary school is being monitored for sound levels. The experiment could revolutionise the construction of schools in the future.
Research being carried out at The Priory primary in Basingstoke, by scientists from Heriot-Watt University, has shown that the echo in the school hall, which was built in the 1850s, lasts for four seconds.
According to Department for Education and Employment guidelines it should be no more than 0.8 of a second.
The reverberations around a building opened in 1994 were found to be no better, while the temporary classrooms erected in 1960 had the best acoustics.
Last week pupils wore "ear defenders" in class while researchers bounced high-frequency noises off the walls and ceilings, and monitored sound levels in different parts of the school.
Headteacher David Hale said: "It has really opened our eyes. We would never have believed that children could miss so much of what is happening in lessons just because of the height of the ceiling.
"Educational psychologists have told us that the hearing deficiencies of children suffering with colds or sinus problems will be even worse.
"The levels of sound reverberation will also vary depending on where a child sits in the classroom.
"The researchers came here because we have such a range of different buildings, spanning more than 140 years in age."
Mr Hale added that the teachers were incorporating the study into maths and science lessons across all age groups.
Heriot-Watt scientists have previously carried out similar surveys at 50 other schools in Scotland, where there were similar findings.
Andrew Smith, marketing manager of Ecophon-Pilkington, which specialises in suspended ceilings and is working with Heriot-Watt at the Priory school on internal structural changes said: "The Swedes cannot believe we have no acoustic controls in this country. In Sweden the maximum echo time is 0. 5 of a second for children with normal hearing and 0.3 for the hearing-impaired.
"It all depends on the height of the ceiling and the materials used in construction. We are using a substance called resin-bonded glasswool, which looks like sheets of plaster board, but is highly sound absorbent and energy-saving."
"It looks like a sheet of plaster, but when you touch it, it depresses slightly."
Mr Smith added:"We found at the Priory that the sound was unbearable in the school hall during assemblies, when there was singing and playing of instruments going on, because of the echo. It was difficult to distinguish the different sounds because of the reverberations."
Resin-bonded glasswool is believed to have attracted the interest of the Department for Education and Employment for its possible future use in schools.
A spokesman for the DFEE said it was unable to endorse any particular product, but suggested that companies producing suitable materials should consult with local authorities.