The UK Civil Aviation Authority (CAA) has rejected criticism of the method used to plot the path of the Icelandic volcanic ash cloud.
Irish budget carrier Ryanair, which has argued that the way in which the presence of ash is calculated is flawed, claimed that the London Volcanic Ash Advisory Centre (VAAC) had admitted that UK Met Office charts showing the position of 'red zone' high-density ash were inaccurate.
This, said Ryanair, had led to the unnecessary cancellation of flights across northern Germany on 25 May.
The CAA responded that while the modelling of the ash cloud's path was theoretical, it was backed up with real-time observations. "We have got total faith in the VAAC model," it added.
The Met Office was not immediately available for comment.