The project was initiated by a request from the Army for a method of dropping heavy equipment and vehicles from aircraft at high speed, retaining the materiel's terminal velocity for as long as possible in order to minimise drift and damage from anti-aircraft gun batteries.
The initial test produced the project's codename; as the rockets' exhaust engulfed the apparatus in a plume of smoke and fire, an attending officer, Captain G. O. C. "Jock" Davies, remarked "Look at it!
However, the implementation of this idea was complicated by the fact that the weight of the plumb-bob would have to be carefully calibrated, heavy enough not to be blown back into the underside of the platform by the extreme upward winds during the fall, yet still sensitive enough to react immediately on hitting "fuzzy" terrain such as heather or long grass.
The earliest tests were made by simply dropping a concrete block from a tall crane (surviving film was shown in the BBC documentary series "The Secret War" in 1978).
After a number of attempts to drop the device ended with hits too far from shore to capture on film, the bomber's crew were instructed to aim as close to the testing facility as possible from a height of 2,000 ft (610 m).
Happily there were no casualties, though the Wren cooks preparing lunch a few feet from the wrecked shelter thought the end of the world had come.On further testing, the initial four-rocket design proved slightly ineffective.
The DMWD attempted to procure a number of jeeps to load onto Hajile for testing the prototype over land, but it proved difficult to convince the Royal Navy to provide working vehicles to jettison from a plane at 2,000 ft (610 m) strapped to an experimental, and potentially explosive, device.
All eight rockets immediately fired and the platform shot forty feet into the air before lurching sideways and crashing back to earth, injuring a number of the crew and blinding one for several days.