TEACHERS at Hounslow Heath infant school often have to pause for 10 seconds a minute to wait for low-flying planes to pass overhead.
"That's a lot of interruptions when you're reading a 20-minute story to a class of six-year-olds," said Kathryn Harper-Quinn, head of the west London school, which is directly beneath the flight-path to Heathrow.
She believes the disruption to lessons is especially serious for her pupils as nearly half have English as a second language.
A poll of teachers by the London borough of Hounslow, which gained 150 responses from 33 schools, found more than seven out of 10 considered aircraft noise a problem in their school.
Of those, 77 per cent said children had difficulty hearing in the classroom and nearly two-thirds said the noise interrupted lessons.
The findings will be outlined in the borough's submission to the Government on the proposed third runway for Heathrow. Ninety-six per cent of the borough's residents oppose the plan.
The worst problems at Hounslow Heath school occur when the airport's southern runway is in use, although the take-off noise from the northern runway can be as bad.
The British Airports Authority has just installed double glazing at the school, as part of its "noise attenuation programme", but Ms Harper-Quinn said this was no use in last week's hot weather.
An air ventilation system, enabling the school to keep the windows closed, will be installed by BAA over the summer.
A spokesperson for the airports authority said only 150 of Hounslow's 2,000 teachers had responded to the borough's survey and nearly a third had reported no problems. The authority was already spending more than pound;1 million on sound insulation, with two more primaries due to follow Hounslow Heath this summer.
But the BAA programme will help only the 10 primaries closest to the airport, whereas 38 Hounslow schools - half of the total - suffer decibel levels well above limits recommended by the World Health Organisation.
Hounslow council estimates it would cost pound;26m to insulate them all fully .
Younger children are often frightened by the noise and the plane shadows passing overhead, said Ms Harper- Quinn. One refugee child thought the noise of Concorde landing was a military aircraft and dived under the table.