Over £25m worth of gold bullion bound for the Far East was stolen from the Brinks Mat warehouse, about one mile (1.6km) outside the airport perimeter, between 0630 and 0815 GMT.

Police have said a group of at least six men overcame the guards and successfully disabled a huge array of electronic security devices.

Insurers have offered a reward of £2m for information leading to the recovery of the 6,800 gold bars - which are all identifiable by refiners' stamps.

The members of the gang - who were all armed and wearing balaclavas - also stole £100,000 worth of cut and uncut diamonds.

Inside information

They dressed in security uniforms to get into the warehouse and then terrorised the guards into giving them the alarm codes.

All the guards were handcuffed, one was hit on the head with a pistol and two had petrol poured over them.

Once inside the safes, the robbers used the warehouse's own forklift trucks to transport the 76 boxes of gold into a waiting van.

The alarm was raised by one of the guards at 0830 GMT after the gang had left.

Scotland Yard Flying Squad chief Commander Frank Cater is leading the hunt for the thieves.

He said he believed they had inside information and were a "highly professional team".

	E-mail this story to a friend