Gordon Brown promises full body scanners at UK airports
Full body scanners remove the need for "pat-down" searches
Prime Minister Gordon Brown has given the go-ahead for full body scanners to be introduced at Britain's airports.
BAA, which runs six UK airports, said it would now install the machines "as soon as is practical" at Heathrow.
Experts have questioned the scanners' effectiveness at detecting the type of bomb allegedly used on Christmas Day in an attempted plane attack over Detroit.
The US is also introducing tougher checks for air passengers from nations deemed to have links with terrorism.
Speaking on BBC One's Andrew Marr show, the prime minister said the government would do everything in its power to tighten security and prevent a repeat of the US attack.
Hand luggage checks
Nigerian Umar Farouk Abdulmutallab, who is now in custody, is accused of trying to detonate a bomb on a plane bound for the US.
Mr Brown said travellers would see the "gradual" introduction of the use of full body scanners and hand luggage checks for traces of explosives.
Brown on Yemen threat and airport security
He added transit passengers as well as transfer passengers would undergo these checks.
Currently, not everyone has to pass through full body scanners already introduced at some major airports overseas - particularly if they are in transit from another country - due to concerns about cost and time delays.
A spokesman for BAA said: "It is our view that a combination of technology, intelligences and passenger profiling will help build a more robust defence against the unpredictable and changing nature of the terrorist threat to aviation."
The spokesman said nothing had been decided yet on exactly which passengers would undergo the full body scans.
And he declined to give specific details about timing or comment on extending the use of scanners to other airports, costs or the potential for passenger delays.
The government's move has been largely welcomed by the Liberal Democrats.
But home affairs spokesman Chris Huhne did say the scanners could have been rolled out sooner as they had been kept in storage since being trialled.
Meanwhile in the US, President Barack Obama promised "to act quickly to fix flaws" in the security system, and condemned lapses following the alleged Christmas Day bomb plot against a US plane.
Reports say people flying from Nigeria, Pakistan, Syria, Iran, Sudan, Yemen and Cuba will have pat-down body searches and have carry-on baggage searched.
Electromagnetic waves are beamed onto passengers to create a 3-D image
The new US security directives will come into effect on Monday.
Philip Baum, editor of Aviation Security International, said scanners were not the only solution and profiling passengers was, in fact, the best way to prevent terrorist acts.
"We've got to face the fact that you can build a bomb in the duty free shop, after you've gone through screening. Bearing that in mind, we need to look at what people's intent is, not what they are carrying on their person."
On Friday, Gordon Brown announced he had ordered a review of existing security measures, and advisers are expected to report within days.
The £80,000 full body scanners, which produce "naked" images of passengers, remove the need for "pat down" searches.
They work by beaming electromagnetic waves on to passengers while they stand in a booth. A virtual three-dimensional image is then created from the reflected energy.
Some have voiced concerns about privacy, with campaigners saying they are tantamount to a "strip search".
The machines are currently being trialled at Manchester airport following tests at Heathrow airport from 2004 to 2008.
They are also being rolled out across the US, with 40 machines used at 19 airports.
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