Hydrogen-powered drone takes flight
25 March 2016 Last updated at 10:07 GMT
BBC Click's Jen Copestake has been given exclusive access to the test flights of a drone powered by a hydrogen fuel cell.
Intelligent Energy's fuel cell can power a modified drone for up to two hours - about six times longer than the average with a normal battery.
Refuelling with compressed hydrogen takes a few minutes compared to recharging a battery.
The company sees its drones being primarily used in industry for agriculture and oil and gas mapping, before being offered as a consumer product.
Intelligent Energy expects to have the fuel cells ready for commercial use in the next year.
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