Smash-and-grab raids on two City jewellers

(PA)

Police have begun an investigation after burglars staged a daring double heist at two of London's most upmarket jewellery shops, getting away with jewels estimated to be worth hundreds of thousands of pounds.

Thieves smashed windows at the De Beers diamond store and an outlet of Omega, the Swiss watch firm, at the exclusive Royal Exchange shopping centre in the City at around 10pm on Saturday.

The raid set off the alarm at the nearby jewellers Tiffany & Co, although it is not believed any goods were stolen from that store. Police were yesterday trying to establish exactly what was taken and its value.

Officers said the robbers arrived in a car and forced their way into the centre, which is closed at weekends, before making a getaway with what they could.

A security guard working at the building, which lies opposite the Bank of England between Threadneedle Street and Cornhill, said staff had been told the robbers entered through the back of the property.

"We've been told that at about 10pm last night a BMW turned up at the back entrance, four men jumped out and managed to get inside the building somehow," he said.

"At the moment we don't know how much has been taken, but, with the price of some of the stuff inside these shops, just a few items could easily run up to a very, very large amount.

"It's looking as though whoever has done this has been targeting the shops for a long time."

CCTV cameras operating in the City log the details of every vehicle driven into the area. Officers are expected to sift through footage to identify the car and examine images from security cameras inside the building.

The front of the Exchange, a Grade 1 listed building built in 1565, boasts a Corinthian-style pillared portico, with the entrance protected by huge green wrought-iron gates.

The shopping centre, which houses high-end stores such as Gucci, Hermès and Cartier, has three other smaller entrances, each of these protected by iron gates.

The raid is the latest in a number of similar incidents that have plagued the capital. A De Beers store at the Westfield shopping centre in west London was targeted in May. At least 10 men wearing balaclavas got into the building complex in Shepherd's Bush and used sledgehammers to break into De Beers and Tiffany & Co. They left with jewellery worth hundreds of thousands of pounds, including diamond rings, bracelets and necklaces.

Groups of thieves riding stolen mopeds and armed with sledgehammers have been involved in several break-ins at jewellers and designer goods shops recently.

Detectives in Westminster set up a specialist squad to deal with the problem and have made dozens of arrests. However, stores in nearby boroughs have since been targeted in a similar way. Last year, robbers stole £40m worth of jewellery at gunpoint from Graff Diamonds in London's Mayfair. Earlier this month, four men were convicted for their part in the robbery.