The quango which advises on classroom computers warns the situation is so bad that ministers cannot meet their target of getting all schools wired up by the year 2002.
Last week, the ministers poured Pounds 235 million into the national grid for learning, an electronic network which will offer training and support materials.
IT is also one of the few subjects protected from last week's curriculum slim-down. Despite its rising importance, the latest technology is scarce in primary schools.
"We're very pleased to see it's rising up the agenda," said Janice Staines, the NCET's the senior programme officer for the National Council for Educational Technology, soon to become the British Educational Communications and Technology Agency. "The difficulty is that schools are not necessarily equipped to use the extra time that has been made available.
"The Government has recognised the problem. But even with the current finance it's going to take longer than five years to get schools on the national grid."
Figures supplied by local education authorities show that schools have only one computer to cater for 18 pupils. And if out-of-date computers are excluded - those more than five years old - then as many as 40 pupils have to share a single machine.
Older computers cannot be used in the creative "multimedia" way suggested in the Government's national grid for learning. Many are unsuitable for the Internet.
Another problem is that older computers use keyboards rather than electronic "mice", which makes them difficult for younger children to operate.
The situation has worsened as many of the cheap computer deals helping schools in the late Eighties and early Nineties are no longer available.