Some 12.5 million unwanted PCs or laptops in the UK have not been re-used or recycled by their owners over the past five years.
Research by Fujitsu Siemens Computers reveals the wastage. Fujitsu says more than one million computers have been dumped in household rubbish or even in the countryside, with about 25% of users taking unwanted machines to their local tip.
The existing waste is a result of only one in two unwanted computers being recycled or donated to another person over the past five years, said Fujitsu.
Only one in 10 Brits said their discarded computer was actually recycled via a manufacturer's recycling facility, and four in 10 said they had given their old computer to a friend or charity.
Fujitsu said municipal tips now needed dedicated IT and electrical waste staff at sites to prevent potentially useful machines being tossed into landfill piles.
The Fujitsu findings come six months after the Waste Electrical and Electronic Equipment directive passed into law, which dictates that users can return unwanted electronic items to retailers and suppliers to be safely recycled.