Fears over airport security could leave millions of passengers facing the indignity of a ‘naked’ body scan and paying higher fares to fund it.

Hi-tech body scanners can see through clothes to detect hidden weapons or explosives such as those used in the failed Christmas Day plot.

They produce an anatomical image of passengers’ bodies, including breasts and genitalia, and have been attacked as too intrusive. Critics have described them as a ‘virtual strip search’.

Home Secretary Alan Johnson said the Government was looking at the use of the full body scanners, but admitted there were cost and privacy issues.