Scientists have deployed Harry Potter-style powers to levitate fruit flies and watch them walk on air.

Researchers performed the seemingly magical feat by suspending fruit flies in a strong magnetic field.

The technique, known as "diamagnetic levitation", allows water and organic based materials to become weightless.

Floating freely inside a plastic tube, the flies were observed closely to spot any changes in their behaviour.

The scientists confirmed effects previously seen in similar experiments in Earth orbit. The flies walked more quickly and more frequently while floating in zero gravity than they did on the ground.

Previously it was not clear whether the changing G-forces associated with space flight may have affected the flies.

The research is published today in the Journal of the Royal Society Interface.

Author Dr Richard Hill, from the University of Nottingham, and colleagues wrote: "This study shows that the walking speed of fruit flies and their 'activity' is altered significantly by counteracting gravitational force.

"Diamagnetic levitation enabled us to maintain tight control over the experimental conditions of all the experimental subjects. This allowed us to identify, unambiguously, the alteration of effective gravity as the cause of the anomalous behaviour.

"Four billion years of evolution have equipped life on Earth to withstand the stresses generated by the ever-present pull of gravity. Here, we have shown that diamagnetic levitation can be used to investigate directly the influence of changing gravity on the locomotion of a complex multi-cellular organism, and that close comparison can be made with experiments performed in space."

Magnetic fields have been used in previous studies to levitate organic materials, as well as small living organisms and even a live frog.

"Diamagnetic material is weakly repelled from magnetic fields, compared with the more commonly known 'magnetic'...materials such as iron, which are strongly attracted to a magnetic field," the scientists wrote. "The diamagnetic force, balancing the weight of the levitating object, acts at the molecular level throughout the body of the object, just as the centrifugal force balances the gravitational force on an object in Earth orbit."