The search is on to track down criminals who broke into a plane at the City of Norwich Aviation Museum.
The site, in the NDR near Norwich Airport, was targeted between 10pm on May 3 and 10am on May 4.
The offenders cut through the perimeter fence then broke into an Avro RJ85 passenger jet - the museum's latest exhibit.
They stole fire extinguishers along with an emergency torch.
Roger Pointing, the museum's company secretary, said: "Fortunately there was not much damage to the aircraft itself so we got away quite lightly in a lot of respects.
"There was a display in the galley that had been swept aside. Items were all scattered on the floor.
"Some volunteers discovered the break-in.
"Getting into the compound itself is quite tricky - they obviously haven't come through the front gates - but they entered in a spot where CCTV is not brilliant. They cut the wire on the fence and climbed over.
"It was a bit of a shock.
"There was some relief because of the lack of damage but it was concerning that people had got in."
Mr Pointing explained that although this is the City of Norwich Aviation Museum's first antisocial behaviour incidents other museums have been targeted with artefacts damaged.
"Unfortunately, the aircraft they got into is a relatively modern commercial jet. They don't tend to have locks on the doors because they're generally stored in secure airports.
"We're trying to incorporate a lock into the door.
"They're not commissioned with locks because when they're in airports, they're in a secure area," he added.
The yobs also tried to access the museum's F27 aircraft which was locked.
The Avro RJ85 came to Norwich's aviation museum around 18 months ago and is the only one on display in the country.
A spokeswoman for Norfolk Police said: "All lines of enquiry have been exhausted, including examining CCTV footage, carrying out house-to-house enquiries and exploring forensic opportunities, and the investigation has now been closed.
"We would of course look at this again should new evidence come to light. The victim has been updated.”
Those with information can contact Norfolk police quoting crime reference number 36/33213/22.
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