The UK's Meteorological office has predicted that volcanic ash will clear northern areas of the country by early 25 May, although it offered no guarantee of a resumption of air services.
Latest Met Office predictive maps show a band of high-density ash lying in a northwest-southeast axis across parts of southern Scotland and northeast England by midnight on 24 May.
The Met Office said that despite the clearing conditions over Scotland it would be up to the UK Civil Aviation Authority, air traffic control provider NATS and individual airlines to determine whether aircraft could fly safely.
The CAA has said that airspace will not be closed, but the ability to fly will depend on individual airlines submitting safety cases detailing their precautions for flying in ash conditions, and these cases being approved by the authority.
Observations of ash have started to be reported. These have included deposits being found on aircraft in the Orkney and Shetland Islands, north of mainland Scotland. In addition, an aircraft flying at 18,000ft (5,486m) in the Manchester area at around 14.00hrs today observed a layer of ash of approximately 1,000-2,000ft thick.
The Met Office predicted that by the end of the week, levels of ash over the UK and Europe should be low. However, this prediction depended on the continuing strength of the eruption and weather conditions.