The scanners show clear outlines of passengers' anatomies
A Heathrow Airport security guard was given a police warning after he was allegedly caught staring at images of a female colleague in a body scanner.
The 25-year-old worker was quizzed by police over alleged remarks he made to his co-worker after she entered a scanner by mistake.
The incident took place at Terminal 5 on 10 March.
It is believed to be the first time an airport worker has been disciplined for abusing a body scanner.
The scanners show clear outlines of passengers' anatomies.
They were introduced at Heathrow and Manchester airports to check for concealed weapons and explosives following the failed Christmas Day bomb plot by Umar Farouk Abdulmutallab to blow up a jet over Detroit in the United States.
Director of Legal Enforcement and the Equality and Human Rights Commission, Susie Uppal, said the incident highlighted the risks to "privacy and respect for human dignity" that are posed by the use of full body scanners.
She said: "It is only through appropriate training and monitoring that we can ensure that the risk of breaches of discrimination and human rights laws by those who take and use the scanned images of passengers are minimised.
"The government has told us very little about what systems are currently in place to ensure that those employed to use the scanners are acting lawfully, with fairness and without discriminating."
She added that the government needed to take urgent and decisive action to ensure that "incidents of this kind are not repeated".
A Scotland Yard spokesman said: "Police received an allegation regarding an incident that happened at Heathrow Terminal 5 on March 10.
"A first instance harassment warning has been issued to a 25-year-old male."