Scotland Yard today released CCTV footage and images of the raid at Joyalukkas jewellers on Green Street in east London.
Burglars smashed a hole in the wall of the shop and crawled inside to steal Indian-style gold and diamond necklaces, bracelets, pendants and earrings.
"This was a meticulously planned and audacious raid on a jewellery shop with 1.8 million pounds of items stolen," said Detective Chief Inspector Andy Pallett from the Met Police's Newham CID (Criminal Investigation Department).
Several men were hanging around the area for a number of hours before the raid.
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"If you have any information no matter how small, please come forward," he said in his appeal relating to the robbery reported to police on July 10.
Joyalukkas, which has its registered office in Kerala, is one of several jewellery shops selling Indian-style gold and diamond jewellery in the Green Street area of east London.
The raid is believed to have taken place in the very early hours of that morning.
Eight suspects are believed to have been involved, with three entering the shop and the rest acting as lookouts.
The three men used a sledgehammer and a crow bar - left at the scene - to create a hole in the rear of the shop which backs onto an alleyway.
Once it was large enough, they crawled inside.
They spent more than three hours inside gathering the jewellery from drawers and counters and stuffing it into rucksacks, the Met Police have concluded.
The remaining suspects acted as lookouts, three of whom watching the shop from 1700hrs on Sunday, July 9, until the raid was complete.
"Footage and images of these men have been released by investigating officers today. One wore a bright pink hooded top, another a black coat and the third a T-shirt and shorts. The other suspects are described as all men with some aged in their mid-30s. The three inside the shop wore gloves and had their faces covered," the Met Police said in its appeal.
There have been no arrests made in relation to the burglary at this stage as the investigation continues.