Controversial body scanners which make passengers appear naked are to be introduced at Birmingham International Airport by the end of the month.
Passengers will be picked at random to go through the scanner - and will be barred from flying if they refuse.
Birmingham International has been ordered to introduce the equipment by the Government, following the failed Christmas Day attempt to blow up a plane travelling from Amsterdam to Detroit.
Nigerian Umar Farouk Abdulmutallab, who studied in London for three years, is standing trial in the US on several charges related to the bomb attempt and has pleaded not guilty.
The scanners beams electromagnetic waves on to passengers to create an image displayed on a computer screen which shows travellers without clothes.
Transport Secretary Lord Adonis said they would be used at Heathrow and Manchester airports immediately, and said scanners would be deployed at Birmingham “over the course of this month”.
Eventually, they will be installed at every airport in the country, he said.
In a statement to the House of Commons, Lord Adonis said: “In the immediate future, only a small proportion of airline passengers will be selected for scanning. If a passenger is selected for scanning, and declines, they will not be permitted to fly.”
However, full body scans could eventually become compulsory for every passenger and Ministers are to launch a public consultation on when they should be used.
Lord Adonis said: “These scanners are designed to give airport security staff a much better chance of detecting explosives or other potentially harmful items hidden on a passenger’s body.”
It was essential to introduce them immediately “given the current security threat level”, he said.
Airports will be barred from selecting passengers to go through scanners on the basis of their race or ethnicity, he said.
But MP Lorely Burt (Lib Dem Solihull) said she would prefer the scanners to be compulsory for all passengers.
She said: “This is a very intrusive process, even if it is necessary for security reasons.
“My concern is that people who are singled out to go through these scanners might understandably feel very resentful.
“I would prefer we take an all or nothing approach. If we need to use these scanners at all then it should apply to everyone.”
Conservatives highlighted the Government’s decision to scrap planned rules which barred airports from using the scanners on children aged under 18.
West Midlands MEP Philip Bradbourn (Con) said: “I am furious that the Government have overturned the laws prohibiting minors from taking part in full body scanning at airports. This is clearly an affront to public decency and the protection of children and it is wholly unacceptable that my constituents and their children are going to be subjected to these intrusive and over the top scans.”
Alex Deane, a barrister and director of campaign group Big Brother Watch, said use of the scanner meant “the terrorists have won”.
He added: “Those upset by the prospect of undergoing these scans shouldn’t be forced to choose between their dignity and their flight.”