Results from broadband speed testers can be significantly inaccurate, according to Virgin Media.
The provider conducted independent lab tests on its 50Mb service which showed that the actual speeds customers are receiving often differ greatly from those recorded by the speed testers.
Jon James, director of group strategy for Virgin Media, says the findings are a concern considering how many customers see speed as a major factor in choosing an internet service provider.
He commented: We are working with speed test sites to help them accurately measure all broadband services, including our new super-fast offerings.
"We will also be helping customers to understand the accuracy of the speed test information."
In response to Virgin Media's findings, Michael Phillips of Broadband Choices told Tech Radar that his website is undertaking a project which hopes to improve the accuracy of the speed test.