A 26 year old man was arrested last week after the box, which contained wires, a timer and a detonator, was delivered to a UPS office in north London two weeks ago, according to Britain's ITV News.

"The government is aware of this incident and takes it very seriously," a transport ministry spokesman said.

"We have already begun an investigation which will look at all aspects of this incident, including UPS's procedures.

"The UK has one of the toughest security regimes for air cargo in the world. All security measures are subject to continuous review," added the spokesman.

The arrested man, who was not suspected of having terrorist links, was granted bail until May.

A UPS spokeswoman said: "Two weeks ago, a suspicious package travelled within the UPS network aboard an all cargo aircraft from the United Kingdom to Istanbul, Turkey.

"UPS is co-operating with the UK Department for Transport's investigation of the incident. UPS has a multiple layered approach to ensure security."