A scanner which produces "naked" images of passengers has started a trial at Manchester Airport.
The authorities say it will speed up security checks by quickly revealing any concealed weapons or explosives.
But the full body scans will also show up breast enlargements, body piercings and a clear black-and-white outline of passengers' genitals.
The airport has stressed that the images are not pornographic and will be destroyed straight away.
Sarah Barrett, head of customer experience at the airport, said most passengers did not like the traditional "pat down" search.
At Manchester Airport's Terminal 2, where the machine has been introduced, passengers will no longer have to remove their coats, shoes and belts as they go through security checks.
Ms Barrett said: "This scanner completely takes away the hassle of needing to undress."
Ms Barrett said the black-and-white image would only be seen by one officer in a remote location before it was deleted.
"The images are not erotic or pornographic and they cannot be stored or captured in any way," she said.
Passengers could refuse to be scanned, she added.