In a demonstration to the US army, a British built solar powered airplane has managed to stay up in the air for 82 hours and 37 minutes.

The Zephyr-6 set an unofficial world record with its flight, using the sun's energy to soar during the day and charge batteries which powered it at night.

The plane was designed by Britiush firm QinetiQ, who claim it could be used for surveillance as well as relaying battlefield communications.

Chris Kelleher, from the UK defence and research firm told BBC News: "The principal advantage is persistence - that you would be there all the time".

"A satellite goes over the same part of the Earth twice a day - and one of those is at night - so it's only really getting a snapshot of activity. Zephyr would be watching all day."

He added that Zephyr could soon be in use with the military: "We think Zephyr is very close to an operational system - within the next two years is what we're aiming for".

"We have one more step of improvements; we trying to design a robust and reliable system that will really sit up there for months; and we want to push the performance."

In the meantime, the team are celebrating their unofficial world record - unofficial because QinetiQ did not involve the FAI (Federation Aeronautique Internationale), the world air sports federation, which sanctions all record attempts.

However, the time did beat the current record of 30 hours and 24 minutes set by US robot plane Global Hawk.

Hit the play button for a vid of Zephyr taking off in a trial last year.