The Iris Recognition Immigration System (IRIS) has received something of a setback, with confirmation from the government scanners had been switched off at half the airports using the scheme.
Manchester and Birmingham airports have mothballed the equipment, leaving only London Heathrow and London Gatwick airports using the system.
The IRIS was introduced at Heathrow in 2005 before being rolled out at Birmingham, Gatwick and Manchester.
The UK Border Agency confirmed the government was reviewing the use of the IRIS system in the light of new technology.
IRIS registration has been halted.