According to a news article in The Independent today. It appears that UK government was unprepared for a volcano eruption in Iceland that could send ash cloud in the direction of UK. Like that did happen in Eyjafjallajökull volcano eruption in the year 2010. But according to the same news the UK government dedicated to drop such plans from there risk assessments and planning in the year 2009. A whole year before the eruption in Eyjafjallajökull volcano took place.
This was most likely also the case in other countries in Europe where the ash cloud did come as a surprise to governments across Europe and they did appear to be unprepared for it when it halted all flights in Europe for almost a week.
News about this.
Government failed to act on volcanic ash threat, say MPs (The Independent)
Emergency plans ‘need scientists’ (BBC News)
The Icelandic news respective. Use Google Translate and expect world of mystery to happen.