The engines cost more than half a million pounds each
Five fire engines in South Yorkshire and the Humber region have been sitting unused since they were bought in 2007, a BBC investigation has discovered.
Each Combined Aerial Rescue Pump (CARP) cost the fire services more than half a million pounds.
However, the vehicles have not yet been used because they are too heavy to be driven legally on British roads.
South Yorkshire Fire and Rescue Service blamed "a supplier's cock-up" for the situation.
The CARP vehicles are designed to do everything a traditional appliance does but they also have an aerial platform on board to allow firefighters access to the upper levels of buildings.
In 2005 the Humberside and South Yorkshire fire services ordered two and four CARPS respectively at a cost of £3m. The first vehicle was delivered to Humberside in 2007.
However, when loaded with equipment, the vehicle exceeded the 26-tonne legal weight for fire engines on the road.
The Humberside service then cancelled order for the second vehicle.
Beverley Sandy, finance and resources director for South Yorkshire Fire and Rescue Service, said: "It's a supplier's cock-up.
"We're very sorry that they're not on the run yet and doing the job they're designed to do, but the problems we've had with them are purely supplier problems."
Humberside fire service said it planned to get its CARP working by Feburary
Humberside's chief fire officer Frank Duffield said: "It exceeded the legal weight for that type of appliance on British roads."
When asked about how the vehicles had come to be purchased in an unusable state, he said: "I can't answer that can I? That's a technical question that perhaps you'd have to ask the manufacturers themselves."
However, the company which supplied the CARPs, TVAC, went out of business 18 months after the issue was discovered.
South Yorkshire Fire and Rescue said it was spending £700,000 to get its four vehicles on the road by Christmas.
The Humberside service said it was modifying its CARP and the vehicle would be ready in February.
If you live in Yorkshire or Lincolnshire you can see more on this story on BBC One's Inside Out at 1930 BST on Monday 25 January. The programme will also be available on the iPlayer.