It would appear that the issue here was not about how much ash there was in the amosphere but where it was. The VAAC model was computer generated and was looking more rediculous by the day as it expanded mathematically over to Newfoundland and into Russia. This was the problem as the satellite imaging used by the FAA showed the ash in a completely different area. Europe started using the satellite imaging as soon as they realised the conflict but because the VAAC couldn't back down we had the farce of Adonis and his advisors insisting on using the VAAC model when there was clearly a vast confliction in the data being provided. A final compromise was thrashed out last night after enormous pressure from the airlines that resulted in a extended red line being drawn round the satellite images.
Standby for massive compensation claims and heads rolling, a typical UK over reaction based on flawed data.