Originally Posted by
seanp7
I understand why this gets flagged, and security and all that, but for a passenger to make it through immigration, security, with a picture ID card or passport in hand, and to be told they have to go back to A gates, all because the "computer says no" is worrying. There has to be a fast, manual option in this case that doesn't involve sending a boarding passenger, who did the right thing, back to the A gates. Waiting for HAL staff to arrive and scan CCTV photos while your flight enters final boarding sounds clumsy.
They do not scan CCTV cameras, they look for the biometric data. Your BP is scanned at conformance and biometrics taken, your PNR will be time stamped with the location and time yoy entered airside. That allows the G4S Security Agent to find your biometrics, if your data is lost you will normally either have to wait for a Border Force Officer or be escorted to the border to be examined by a Border Force Officer, once Border Force are happy with your status you will be landed/boarded and you will be allowed to continue your journey.