Three raiders were caught on camera using specialist diamond cutter tools to steal a famous ‘national treasure’ tiara.
In the footage, which has just been released by police, the burglars are seen breaking into an estate and making a beeline for the piece.
A diamond brooch was also swiped from the armoured glass display.
Police were called to the Welbeck Estate in Nottinghamshire on November 20 following the theft.
The footage released by the force features three suspects who are wanted in connection with the incident, which took place between 9.45pm and 10pm.
Police said they are also appealing for information about a silver Audi RS5 Quattro, registration number KY61 USJ, which is believed to have been involved in the crime.
The car was stolen from the Phoenix Park park and ride tram stop on Millennium Way East on November 2 and was found abandoned and burnt out in Blidworth, around 30 minutes after the burglary.
Detective Inspector Gayle Hart said: ‘Our inquiries are ongoing and we’re making a plea to potential witnesses.
Caption: Undated handout photo issued by Nottinghamshire Police of a diamond brooch which was stolen by three raiders who used specialist diamond cutter tools from the Welbeck Estate on November 20. PRESS ASSOCIATION Photo. Issue date: Thursday December 6, 2018. The brazen burglars broke into the Portland Collection Gallery and stole The Portland Tiara from an armoured glass display as well. See PA story POLICE Tiara. Photo credit should read: Nottinghamshire Police/PA Wire
NOTE TO EDITORS: This handout photo may only be used in for editorial reporting purposes for the contemporaneous illustration of events, things or the people in the image or facts mentioned in the caption. Reuse of the picture may require further permission from the copyright holder.
Photographer: Nottinghamshire Police
Source: PA’The suspects were wearing white suits and motorcycle helmets but we’re still hoping someone may know who they are and we’re urging anyone with any information to get in touch with us.
‘We’re also urging anyone who has any information about the silver Audi RS5 to contact us.
‘We’re keen to trace this vehicle’s movements preceding the burglary, so again we’re appealing to anyone who saw it or who has any information to get in touch with us as soon as possible.
‘We believe the burglars used specialist diamond cutter-type tools to break through the armoured glass display case.
‘If anyone has information about people hiring or sourcing such equipment then we’d urge them to get in touch.’