LONDON: A parcel bomb sent from Yemen and removed from a cargo plane at a British airport last month was timed to explode over the eastern seaboard of the United States, Scotland Yard said Wednesday.

The plane arrived at East Midlands Airport in central England from Cologne in Germany in the early hours of October 29 and the package hidden in a printer ink cartridge was removed from the aircraft.

The aircraft operated by parcel delivery company UPS took off just over two hours later, heading for Chicago.

“Forensic examination has indicated that if the device had activated it would have been at 10:30hrs BST on Friday, 29 October 2010” the Metropolitan Police said in a statement.

“If the device had not been removed from the aircraft the activation could have occurred over the eastern seaboard of the US.”

Police added that the device was “disrupted” at East Midlands Airport by explosive officers during the initial examination when they removed the cartridge from a printer some three hours before the bomb was timed to go off.

The Yemen branch of al Qaeda last week claimed responsibility for the plot, according to the monitoring website SITE.

French Interior Minister Brice Hortefeux claimed in the days after the bomb was discovered that British anti-terror police disarmed the device just 17 minutes before it was due to detonate.

The bomb was one of two packages sent from Yemen and addressed to synagogues in Chicago containing the hard-to-detect explosive PETN, sparking a global scare. The other package was discovered at Dubai airport.

Al Qaeda in the Arabian Peninsula (AQAP) is also thought to be behind a number of recent attacks, including last year’s Christmas Day “underpants bomb” scare, in which a Nigerian student smuggled a PETN-based device onto a US-bound passenger flight.

That device failed to fully explode, and the plane landed safely.

Last week, a British court sentenced a 21-year-old woman student to life in prison after she stabbed and tried to kill a former government minister after listening to AQAP propaganda online.

The British government announced an urgent review of air freight security in the wake of the printer cartridge plot. It has also ordered the suspension of all air freight from Yemen and unaccompanied air freight from Somalia.

Britain’s interior minister Theresa May told parliament last week that the bomb was “deeply concealed” in a printer cartridge and connected to a hidden power source in sections of a mobile telephone.

“The specifics of this attack — notably the type of device and how it was concealed — were new to us,” but the principle was similar to the device that destroyed a Pan Am jumbo flight over Lockerbie, Scotland in 1988, May said.

As part of new security measures brought in following the foiled attacks, countries sending airfreight to Britain will be “graded” according to risk, transport minister Philip Hammond said.

German officials said the two bombs found in Britain and Dubai contained between 300 and 400 grammes of PETN apiece. The explosive is difficult to detect and easy to pack into seemingly innocuous devices.