LONDON -- The government has ordered an investigation of Heathrow Airport security, a day after two men robbed a van of $6.5 million that had been unloaded from an airplane.
Home Secretary David Blunkett and Transport Secretary Stephen Byers both called the robbery a "serious breach" of security.
They said they want to know how thieves gained access to the airport's restricted zone during a period of heightened security in the wake of Sept. 11.
The two robbers held up the security van Monday, escaping with the cash in several currencies that had arrived on a passenger plane from Bahrain.
The money was in transit from Bahrain through Heathrow to Kennedy International Airport in New York.
The van driver was attacked by two men in a secure area at the airport's Terminal 4 at about 6:30 a.m., police said.
The robbers forced him to the ground and bound his feet and wrists before putting the cash, which had just arrived on British Airways with 187 passengers aboard, into a second airline van.
The theft of the eight red cargo boxes occurred as passengers left the plane and it was being refueled.
Within five minutes, all airport security gates were closed, but the robbers were already gone, police said.
Some officials speculate the robbery may have been an inside job.