New security rules in the UK have made it compulsory for some passengers to pass through full body scanners at Heathrow and Manchester Airports.
Passengers selected for a scan must now take part or risk not being allowed to fly.
The full body scanners at Heathrow and Manchester have raised concerns over the breach of passengers' rights to privacy.
The scanners will also be installed at Birmingham Airport later this month ahead of a national rollout.
Transport Secretary Lord Adonis said only a small proportion of passengers would be selected for scanning.
The UK Department for Transport has published an interim code of practice for airports covering privacy, health and safety, data protection and equality issues to protect passengers.
According to the code of practice, security officers will view the images remotely and passengers will be able to request that their images be viewed by someone of the same sex.
Security officers will have to obtain appropriate security clearances before receiving training approved by the Department for Transport.
The new rules have been introduced following the alleged attempt to blow up a US-bound plane over Detroit on Christmas Day by the Nigerian passenger Umar Farouk Abdulmutallab.