London's Olympic Park construction site is to be turned into a "virtual fortress" protected with state-of-the-art biometric security measures that will allow only workers who have been scanned to get into the compound.

From this week machines that are capable of hand and iris recognition will be installed at entry points around the 2.5 sq km site, which, given its high-profile status as Europe's largest regeneration project, is considered a major terrorist target.

The hand scanners are capable of checking up to 5,000 workers an hour and will be used alongside photographic smart cards. The iris-scanning system will be available as an alternative when required.