Plane carrying hidden bomb declared safe in airport search

How close the bomb plot could have come to fulfilling its devastating aim became clearer yesterday, as Prime Minister David Cameron said he believed the UK device was intended to blow a plane out of the sky while Home Secretary Theresa May said it could have taken down the plane anywhere on its route.

Fears more devices could yet be in transit have led the Government to ban all unaccompanied freight from entering the country from Yemen, where the bombs originated, and US officials have travelled to the country to oversee cargo security procedures.

It emerged yesterday that officials at East Midlands airport at first gave the device the all clear following a six-hour sweep of cargo on the UPS plane. It was only following the discovery of the Dubai device that British authorities were urged to look again, whereupon the bomb was found.

Responding to claims only a precise tip-off from Saudi Arabia had prevented the attacks from succeeding, Home Secretary Mrs May said a review of search procedures was under way. A Metropolitan Police spokesman said: "The package was examined and declared safe. It was subsequently re-examined as a precaution."

The explosives are understood to have contained the powerful explosive material PETN, which is hard to detect.

In Yemen a woman arrested over the weekend in connection with the bomb plot was released last night. Hanan al-Samawi, 22, a female computer engineering student, was detained on suspicion of mailing the packages addressed to synagogues in Chicago.

She was detained because her telephone number appeared on one of the packages. Police in Yemen said the release was conditional and she could still be questioned further.

Yemeni security officials also claimed at least five other suspects have been arrested and interrogated, with a number of employees of shipping companies, including two from freight specialist FedEx, under investigation.

American deputy national security adviser John Brennan said that while nobody had claimed responsibility for the attacks they bore all the hallmarks of al- Qaida.

Meanwhile the Saudi-born bomb-maker Ibrahim Hassan al-Asiri has been named by the US as the prime suspect for constructing the devices.

Al-Asiri is also believed to have been responsible for making the device involved in the failed Christmas Day bomb plot over Detroit last year.

Qatar Airlines said an explosive device travelled from the Yemeni capital Sana'a to Doha International Airport before being loaded into another plane and on to Dubai. The device found in Britain had also travelled from Yemen via Germany, with its final destination the United States.

Qatar Airways said in a statement on its website: "The explosives discovered were of a sophisticated nature whereby they could not be detected by X-ray screening or trained sniffer dogs. The explosives were only discovered after an intelligence tip-off."

The difficulty of detecting the devices was also raised in the UK, with Lord Carlile, who reviews the Government's anti-terrorism legislation, saying the UK must ensure all of its anti-terror equipment remained up-to-date.

The Home Secretary said the terrorists would not have known exactly where the deadly device would explode and said the Government was in talks with the air industry about further restrictions.

"We are going to be looking at the security that we adopt in relation to freight. We will be talking to the industry about those measures," Mrs May said.

"What became clear overnight Friday and into Saturday was that it was indeed a viable device and could have exploded.

"It could have exploded on the aircraft, and it could have exploded when the aircraft was in mid air. Had that happened it could have brought the aircraft down."