There are not enough desktop computers, laptops or interactive whiteboards in secondary schools, despite billions spent on them.
In eight years, more than pound;3 billion has been spent on computers for UK state schools. But research by Becta, Britain's education technology agency, suggests that teachers' demands for equipment are outstripping availability in schools.
Almost half of the 258 secondary schools surveyed said they needed more computer equipment.
But Becta's Harnessing Technology study found greater satisfaction among teachers at the 233 primary schools surveyed although 40 per cent still felt more laptops were needed and 25 per cent wanted additional desktops.
Ray Barker, director of the British Educational Suppliers Association, which represents companies selling equipment to schools, said the dissatisfaction was down to more teachers wanting to make the most of technology.
"Now that teachers realise its advantages, there are never enough computers and they are never in the right place," he said.
Becta research also indicated that, counter to expectations, the ratio of computers to primary pupils has reduced: in 2005, there was one for every six primary pupils; this year the figure is nearly seven.
Terry Freedman, chairman of the ICT subject association Naace, suggested the dip might be a result of schools buying other types of technology, such as digital cameras.
The survey showed that use of wireless connections has soared in the past two years, with 80 per cent of secondaries and 50 per cent of primaries now making some use of the technology, despite safety fears from campaign groups.
And 75 per cent of primary teachers and 50 per cent of secondary teachers said ICT saved time in lessons. The majority said it helped boost pupils' motivation and attainment. Some complained that using technology actually wasted class time and 20 per cent of secondary teachers said they lost time using ICT in lesson planning.
The survey also examined how satisfied teachers were with specific types of technology.
Interactive whiteboards received the highest satisfaction rating from teachers. Hand-held computers got the lowest, although 63 per cent still rated them as good or quite good. Only a handful are being used in primary classrooms and the number has dipped since last year.
By 2008, all schools are supposed to provide pupils with "learning platforms" or online workspaces.
But the survey suggests that only 11 per cent of primaries and under 50 per cent of secondaries are on course to achieve this.
Balsall Common Primary in Solihull, West Midlands, has won awards for its use of technology. Christian Hamilton, its ICT manager, said schools often had difficulty funding technology despite billions spent.
"The head, governors and parent teacher association here all support putting school fundraising towards technology, so we can do everything we would like to, but that's not the case everywhere," he said.
Some schools might not feel they have adequate technology, Mr Hamilton said, because they have not invested in the maintenance of existing hardware.
Primary and secondary schools both told researchers their future priority would be technical support.
Mike Kent, head of Comber Grove Primary in Camberwell, South London, has words of comfort for schools that lack the latest equipment. His school has interactive whiteboards in every class and laptops, but he still uses a 1980s BBC Micro to do school accounts.
"Technology should not be the be-all and end-all," he said. "Children sometimes need to sit down with a cornflake packet and washing-up liquid bottle and tell you it's a spaceship."
* 'Harnessing Technology' can be found at www.becta.org.uk