This is a satellite image from the British Met Office from 08.30 this morning (Friday 16th April, 2010) showing the volcanic ash plume (in orange) drifting downwards over UK and Irish airspace. You can see a full sequence of these images (one taken every 30 minutes) on the Met Office website.
The British Met Office is one of nine global Volcanic Ash Advisory Centres (VAAC) which monitor all volcanic eruptions worldwide for their potential impact on air travel. It is one of only two World Area Forecast Centres (the other one is in Washington) and provides forecasting of upper winds and temperatures for all flights throughout the world. This enables airlines to optimise safety and fuel consumption for their aircraft.