Police in London say they have foiled an attempted robbery of £40 million in cash and precious metals from a warehouse at Heathrow Airport. Six men were arrested.

In a statement, the Metropolitan Police said the men rammed into the warehouse in a white van.

They attempted to steal the metals and then force their way into a secure area containing bank notes, at about 10am this morning.

The men in custody are in their 30s and were arrested at the Swiss Port Cargo Warehouse, in an operation involving more than 100 officers - some of them armed.

They threatened staff with at least one gun, knives and cudgels.

It is understood members of Scotland Yard's Flying Squad swooped after receiving intelligence.

Officers are searching for two men who escaped from the scene after hijacking a van. The driver is safe and well.

An airport spokesman said he understood the incident was outside the airport's southern perimeter road, and did not affect its operations.