Aviation authorities in the UK are closely monitoring the fall out from a volcanic eruption in Iceland, where planes have been put on high alert.
Iceland's Met Office this afternoon reported a subglacial lava eruption at the Bardarbunga volcano, which has been rattled by thousands of earthquakes over the past week.
In 2010 an eruption of the Eyjafjallajokull volcano, in the south of the country, produced an ash cloud that caused a week of aviation chaos with more than 100,000 flights cancelled across the UK and the rest of the world.
A spokeswoman for NATS, the UK's air traffic control organisation, said: "NATS is monitoring the situation and working in close collaboration with the Met Office, Department for Transport and our safety regulator, the Civil Aviation Authority, as this dynamic situation develops further."
She added that NATS will help determine what impact the eruption will have for operations in UK airspace and advise airline customers accordingly.
Just minutes before the eruption Iceland raised its aviation alert to the highest level of red, which warns that an eruption could cause "significant emission of ash into the atmosphere."
A spokesman for budget airline easyJet said it is putting its contingency plans into action following the red alert, using specialist technology to ensure any ash created by the eruption is detected and chartered.
"easyJet will use this and other data provided by the authorities to determine what, if any, changes it should make to its flying programme," he said.
"As things stand there are no changes to easyJet's flying programme, including flights to and from Iceland."
He added: "The safety and wellbeing of our passengers and crew is easyJet's highest priority."
Aviation chiefs are confident that the UK is much better prepared to deal with a potential ash cloud crisis than it was four years ago.
Earlier this week a Nats spokeswoman said: "Even in a worst-case scenario we are in a much better position to deal with this than we were in 2010."
The Civil Aviation Authority said: "Volcanic ash can adversely affect aircraft in a number of ways. Jet aircraft engines in particular are susceptible to damage from volcanic ash.
"That's why there are comprehensive safety arrangements in place. As a result of the work that has been undertaken since the 2010 ash crisis and arrangements that have been put in place since, we are confident that high levels of public safety can be maintained, while minimising disruption."
The CAA said the improvements include:
:: A new system of regulating the way aviation deals with ash that allows more airspace to be used safely and gives airlines more input into the process;
:: Improvements in the observing and forecasting of where ash is and its density - including a new radar in Iceland to detect ash in the atmosphere;
:: The establishment of two working groups including airlines and scientists to act as advisers on ash forecasting and how best to use the output from the Met Office modelling system.
A spokeswoman for the Met Office said: "We are in close contact with the Icelandic Met Office, but currently they tell us that the eruptions are sub-glacial, so no ash has made it to the surface.
"If ash does make it to the surface, we will run our model which will indicate where any ash would go, and we will inform the CAA and Nats. They will then make the decision on how that will affect any air flights."
A Virgin Atlantic spokesman said a flight from London Heathrow to San Francisco was rerouted away from the volcano as a "precautionary measure".
" Safety and security is always our top priority," he said.
"All other Virgin Atlantic flights continue to operate as normal, but we are advising all customers to visit our website for the latest information.
"We continue to closely monitor the situation and we are in ongoing dialogue with all of the relevant authorities."
Andrew McConnell, Flybe's director of communications, said: "We are monitoring the situation in Iceland very closely, currently there is no disruption to our services and all our flights are operating as normal. "