Burglars escaped with a haul of jewellery worth an estimated £80,000 after breaking in through the roof of an antiques centre near York Minster.
The gang, who were dressed in black and wore headtorches, lifted tiles from the roof of Red House Antiques Centre on Wednesday evening before smashing through the ceiling into an office below.
They then swept through the showroom area, shattering the glass of display cabinets and rapidly selecting the most valuable items.
Owner Tim Hogarth, a regular on ITV shows Dickinson's Real Deal and Secret Dealers, said the burglars spent as little as three minutes inside the building before making their getaway.
"They came in through the roof after taking the tiles off," he said. "They smashed the glass display cabinets and emptied them out. They had been in there obviously and knew which cabinets had high value items in them. It's purely jewellery that they were targeting."
He said police believe the culprits are the same people who have targeted other centres in the area, making off with antiques and jewellery worth more than £1m after breaking in through roofs or walls.
"There was one in Harrogate where they came in through the roof," Mr Hogarth said. "They knew what they were doing. They were all in black with headtorches on. There was no DNA left."
In this case, the initial estimate for the items believed to have been taken runs to around £80,000.
Mr Hogarth is now working with the investigation team to establish exactly what is missing, provide detailed descriptions and source pictures where possible.
He said: "There's some quite distinctive things - diamond rings, a gold card case in a fitted presentation case, things like that which you don't necessarily see all the time."
The antiques centre has been trading for around 20 years, but Mr Hogarth took over the business in Duncombe Place around five years ago.
"We get a bit of shoplifting, but it's the first time the business has been targeted in this sort of way," he said.
"We were closed yesterday. There was an awful lot of broken glass and debris, and the office where they came in was a complete mess.
"It's a bit of a hit really, but we want people to know we're back trading and it's business as usual."
He urged anyone with information to contact police, adding: "If somebody comes along with a haul of jewellery, I would be very suspicious about where it's come from."
A North Yorkshire Police spokeswoman said: “The investigation is ongoing to trace those responsible after significant amount of jewellery and antiques was taken from the Red House Antiques Centre in York on Wednesday evening."
Anyone with any information which could help the investigation is asked to call North Yorkshire Police on 101 and pass information to the Force Control Room for incident 12180185298.
Alternatively, call the independent charity Crimestoppers in confidence on 0800 555 111.