A motorcycle gang grabbed $3.25 million of jewels from an exclusive London store in just 39 seconds in a raid captured in dramatic detail on closed-circuit TV.

Six robbers on three motorcycles roared up the pavement to Mozafarian jewellers, just across the street from the giant department store Harrod's of London.

One of the robbers smashed open the glass door with a sledgehammer before the gang, all wearing crash helmets, stormed in and smashed open display cabinets.

The haul of gems included a $820,000 diamond necklace. However, the robbers were unable to break their way into one display case containing further $4 million of gems.

Pouya Nikomagham, a sales assistant at Mozafarian, said that the highly organized gang members did not say a word as they raided the store.

“They were very professional, they knew what they were doing and where to go,” said Nikomagham.

Click here for more on this story from the Times of London.