Google has been at pains to remind users that Glass itself does not include facial recognition, and has come under pressure from American senators to answer questions they claim the wearable computer raises over privacy. But the device's terms and conditions do not explicitly forbid using the device’s camera to detect faces and then to identify them via Glass’s screen, which sits above the user's right eye and is visible only to them. The terms do, however, forbid diverse other actions including developers reselling Glass or using it to make money from advertising.

The first version of Lamda Labs software forces users take photographs, tag them with information on who is in them and then compare any subsequent photographs taken to those previously uploaded. Future versions, however, may allow real-time recognition of faces.

The company already makes software that allows the recognition of faces in digital photographs, and claims it is in use by 1,000 developers whose work generates 5million attempts at recognition per month.

Developers on Twitter suggested that the new integration with Google Glass could help with new applications for doormen to make admission to events simpler, software for the disabled and even a new way to make finding friends in a crowd easier. It could also identify people and link them to their Facebook or LinkedIn profile.

Google has previously stated that “We’ve consistently said that we won’t add new face recognition features to our services unless we have strong privacy protections in place.”

The company currently emphasises that Glass is not a product yet fit for public consumption, and limits its uses to internet searches and finding directions. It argues that the device will remove the barriers to social interactions currently formed by mobile phones.