The patent is believed to be the result of research in the 1970s that led to the Prestel system which allowed users to send messages and access screen-based information from third party servers. The technology was not popular because it pre-dated the affordable PC.
BT sought patents in countries other than the US, and these have already expired. However, because the US patent office did not formally accept BT’s application until 1986, its US patent still has six years before expiry.
It appears that the patent was forgotten about until a routine audit of intellectual property about two years ago. BT has sent letters to ISPs in the US and has instructed QED, a company which helps companies win revenues for patents that have not been exploited.
In a statement yesterday, BT said, “We are not trying to stop anybody using the internet, we simply want some reasonable royalties based on the revenues other organisations are enjoying from using this intellectual property.”
It is likely that BT will face much legal opposition in its attempt to enforce a patent that strikes at such a fundamental component of the internet. The company said it waited two years since it rediscovered the patent to ensure that it was ready to exploit it properly.