Britain could re-open some of its airspace on Tuesday after a 'dramatic' decrease in ash thrown up by a volcano in Iceland, transport minister Andrew Adonis said. 'It may be possible to start opening some UK airspace tomorrow, and if it is, contingency arrangements are being put in place to get as many people back as soon as possible in this window that may open,' he told Sky News television. 'During the course of this morning there has been a dramatic decrease in volcanic activity from Iceland. This is being analysed' by the Met Office and the National Air Traffic Services (NATS), he added. Adonis said that authorities are working on contingency plans to bring home some of tens of thousands of Britons stranded abroad if a 'window' opened in the ash cloud over large parts of Europe. The comments came ahead of a video conference between European Union (EU) transport ministers to discuss their response to the volcanic ash cloud, which has grounded flights across much of northern Europe for five days. 