Five fire engines in South Yorkshire and Humberside have been sitting unused since they were bought 2007, a BBC investigation has discovered.
Each Combined Aerial Rescue Pump (CARP) cost the Fire Service more than half a million pounds.
However, the vehicles have not yet been used because they are too heavy for 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 a special lifting device on board to allow firefighters access to the upper levels of buildings.
'Very sorry'
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 of 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'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 somebody's life is in danger, what difference does it make if they exceed the legal weight limit or not?
