Media playback is unsupported on your device Media caption During a test flight of the Met Office Civil Contingency Aircraft, scientist Joss Kent explains how they detect an ash cloud

A network of ash detectors is to be installed across the United Kingdom to help prevent volcanic ash cloud shutting down European airspace.

An ash cloud from Icelandic volcano Eyjafjallajokull led to airlines cancelling flights in 2010.

Aviation authorities and the Met Office were accused by some airlines and politicians of overestimating the threat to aircraft.

At that time, aircraft could not fly if there was any ash in the atmosphere.

All of this prompted an international effort to improve forecast capability and the aviation authorities to change their flight safety rules.

The cost of closing the airspace cost airlines more than £1bn.

"We've got three bands of ash - low, medium and high, which is defined by the amount of ash in the air - that defines where airlines can fly," said Jonathan Nicholson of the Civil Aviation Authority.

"If the airline has arranged with us that they can fly in the low and medium bands, then they're free to make their own choices. So we should see much less disruption with the same amount of ash as we saw during the Icelandic volcanic ash cloud."

'Minimising disruption'

Working out whether an ash cloud is low, medium or high is where the new government-funded network comes in.

It will be made up of 10 instruments called Light Detection and Ranging Systems, or Lidar.

Media playback is unsupported on your device Media caption Joss Kent takes Peter Gibbs on a tour of the plane

The equipment uses lasers to work out how dense a layer of ash cloud is and that data can be used to work out if that cloud is safe to fly through.

Aviation Minister Robert Goodwill said: "This new equipment will allow the UK's Met Office to track ash clouds more easily and predict how they might spread more accurately.

"That could play a big part in minimising disruption to flights during any future incident."

The ground-based network will be used in conjunction with the world's only plane specifically kitted out to detect volcanic ash particles.

The Met Office Civil Contingency Aircraft, or MOCCA, has its own Lidar and so that data will be added to that collected from the ground network to help formulate the ash cloud forecasts.

Data gathering

Met Office scientist Joss Kent has been one of the driving forces behind MOCCA.

"The Lidar has a laser that reflects off clouds and goes into a telescope, within the instrument, which detects the reflected laser light," he said.

"If particles in the cloud are volcanic ash they will reflect in a different direction compared to other particles due to its shape - and the Lidar can measure that change in direction.

"If a cloud's not too thick the laser is powerful enough to fire all the way through that layer and we can see out the other side, which is useful for us as we know it will be safe the other side to fly."

Mr Kent added that the data is transmitted in real time from the aircraft to Exeter, where it is examined to determine how to adapt the forecasts.

The added of advantage of the MOCCA being used with the new network is that the aircraft will be able to get more targeted measurements of ash in areas that the ground-based network cannot see.

Media playback is unsupported on your device Media caption Joss Kent and Peter Gibbs discuss the dangers of the flying the Met Office Civil Contingency Aircraft

Aircraft technology

Airlines have also been taking the initiative. Easyjet has been testing an ash detector, which they hope to fit to some of their aircraft in future to give early warning of any ash in the flight path ahead.

Meanwhile, British Airways have flown an experimental instrument on one of their jumbo jets, which measures the static electricity generated by the friction of an aircraft flying through ash to try and assess the concentration.

However, the Civil Aviation Authority will need to approve these instruments before they can be brought into use.

Mr Nicholson said the technology the airlines are working on fitting to their aircraft would be to enable them to see what ash was in front of them.

"That will be a big help, especially when you combine it with other things like the new radar, satellites, ground based detection system and the test aircraft."

The active volcanoes of Iceland will continue to present a risk to air travel in future, but the combination of improved detection, better forecast capability and more flexible safety regulations will minimise disruption next time around.