Ash from a volcanic eruption in Iceland is predicted to spread south, reaching part of northern Britain by Tuesday and raising the possibility that flights could be disrupted.
The Grimsvotn volcano is the country's most active and began erupting late on Saturday.
The British Metrological Office says the ash does not mean that air space will definitely close, but disruption is more likely, the BBC reports.
Europe's air traffic control authority says the cloud may arrive in Spain and France later in the week.
Icelandic air traffic control has created a no-fly zone around the volcano, closed the main Keflavik airport and cancelled all domestic flights.
Grimsvotn lies beneath the Vatnajokull glacier in southeast Iceland. It has erupted nine times between 1922 and 2004.
In April last year, the nearby Eyjafjallajokull volcano erupted, shutting down large swathes of European airspace amid fears the volcanic ash could wreak havoc on aircraft engines.
An estimated 10 million passengers were affected when all planes were grounded in northern Europe for five days.
In November 2004, volcanic ash from Grimsvotn fell on mainland Europe and disrupted some flights to and from Iceland.
