Civil liberties campaigners have criticised the scanners as an invasion of privacy

The passenger was at Manchester Airport for a flight to Islamabad when she was selected at random to pass through the controversial security screen.

She was warned she would not be allowed to board the Pakistan International Airlines flight if she did not comply with the request but she decided to forfeit her ticket and left her luggage at the airport.

Her female travelling companion also left the airport after she cited ”medical reasons” for not wanting to go through the scanner.

More than 15,000 people have already passed through the £80,000 Rapiscan machine at the airport’s Terminal 2. The Government introduced the scanner at Heathrow and Manchester airports last month.

Security staff use the X-ray machine to check for any concealed weapons or explosives but it has attracted criticism for also showing clear outlines of passengers’ genitals. Civil liberties campaigners have criticised the scanners as an invasion of privacy.

Sources at Manchester Airport said the flight to Pakistan about two weeks ago was busy and that no other passengers objected when chosen to go through the full body scanner after check-in.

The female passenger who declined on medical grounds was said to be concerned because she had an infection.

It is understood the women may be the first passengers in the UK to be barred from taking a flight after refusing to submit to the scan. Heathrow Airport said it could not comment on individual cases.

A Manchester Airport spokeswoman said: ”Two female passengers who were booked to fly out of Terminal 2 refused to be scanned for medical and religious reasons.

”In accordance with the Government directive on scanners, they were not permitted to fly.

”Body scanning is a big change for customers who are selected under the new rules and we are aware that privacy concerns are on our customers’ minds, which is why we have put strict procedures to reassure them that their privacy will be protected.”

Last month, Transport Secretary Lord Adonis stressed that an interim code of practice on the use of body scanners stipulated that passengers would not be selected ”on the basis of personal characteristics”.

He stressed that images captured by body scanners are immediately deleted after the passenger has gone through and that security staff are appropriately trained and supervised.