A loophole which allowed airmailed packages to enter and leave Britain without being checked is to be closed as part of a tightening of security in the wake of the air cargo bomb plot.
Countries sending freight into the country will also be given a "safety grade", with more resources devoted to packages from dangerous regions and less applied to parcels dispatched from nations regarded as safe.
The new measures were agreed during an emergency meeting between Philip Hammond, the Transport Secretary, and senior executives from Britain's major airlines, airports and parcel companies.
The new rules will be tested over the next few days to ensure they are workable, before being formally agreed by the Government's National Security Council in a few weeks' time. Bans on freight from Yemen and Somalia have already been put into place.
"There is no doubt in my mind that the greater area of weakness is in inbound cargo to the UK from airports where standards are variable," Mr Hammond sad last night. "We shall be categorising countries of origin according to layers of risk."
Rescreening cargo that travels through Britain as part of its journey is a direct response to last weekend's foiled bomb plot. The device discovered on a UPS courier aircraft at East Midlands Airport had stopped temporarily en route to Chicago. A second device, also dispatched from Yemen, was found in Dubai.
Parcels heading through Britain from Delhi, Doha, Khartoum in Sudan, Islamabad, Karachi and Lahore will now be checked.