Heathrow is to become the first of BAA’s six UK airports to install full body scanner. The airport operator said the scanners would be in place “as soon as practically possible”.

The move follows Prime Minister Gordon Brown saying the UK was committed to using the new technology, and that airports had to “go further” on security measures following the foiled terror attack on Christmas Day by a suspected Nigerian Al Qaeda terrorist.

Brown announced tighter security measure across UK airports, including checks for explosives on hand luggage and controls on transit, as well as the full body scanners.

The move came as the US and British embassies in Sana’a were closed for a second day after security threats from a Yemen-based al-Qaeda group that has claimed responsibility for the US attack.

BAA, the Ferrovial-owned operator that runs six UK airports, said the scanners would be rolled out at Heathrow first.

It said in a statement: “Now that the government has given the go-ahead, we will introduce full body-scanners as soon as [practicable].”

However it did not put a time scale or cost on the project or to say which flights would be covered.

But critics have questioned the effectiveness of full-body scanners in detecting the explosive used in the Christmas day attack. There are also privacy concerns over the devices, which produce “naked” images that campaigners assert are tantamount to a strip search.

Mr Brown conceded that the scanners, which have been trialled at Manchester airport, do not offer a catch-all solution.