The Icelandic ash cloud causing chaos for air travellers was Wednesday set to blow from Britain towards Germany, forcing airports in the north of the country to close. Around 500 flights were grounded Tuesday as ash from the Grimsvoetn volcano swept across northern England, Scotland and Northern Ireland, but was to clear from British airspace early Wednesday, air traffic control experts predicted. Meanwhile, German air safety officials announced that no flights would land or take off from Bremen Airport after 5:00 am Wednesday and Hamburg Airport after 6:00 am as the cloud drifted towards continental Europe. The disruption comes barely a year after a similar eruption in Iceland forced the biggest closure of European airspace since World War II. British Airways led the way in cancelling flights as the plume spread eastwards, followed by Dutch airline KLM, Ireland\'s Aer Lingus and budget airlines easyJet and Ryanair. \"Approximately 500 flights were cancelled from the approximately 29,000 that would have been expected today across Europe,\" said a statement from Brussels-based air traffic controllers Eurocontrol. The ash cloud caused minor air traffic disruption in Norway and closed a small part of Denmark\'s airspace on Tuesday, and Eurocontrol warned there was a \"strong possibility\" that it would spread to southwest Sweden by Wednesday. \"This would have some impact on flights. However, given the new procedures in place and the predicted movement of the ash cloud over the coming days, the actual impact on flights is expected to be relatively low,\" it said. British air traffic control company National Air Traffic Services (Nats) confirmed the ash was moving away from Britain. \"Latest information from the Met Office shows that following the recent eruption of Grimsvoetn in Iceland, no volcanic ash is currently predicted in airspace over the UK from 0100 UK time on Wednesday May 25,\" a Nats statement said Authorities say the ash can damage planes and stop engines, but Ryanair flew a plane through Scottish airspace and said it detected no ash on the aircraft. It accused British and Irish authorities of over-reacting but reluctantly cancelled its flights to and from Scotland -- almost 70 in total. British Airways conducted its own \"verification\" flight later Tuesday, sending out an Airbus A320 from Manchester Airport to assess the risk over northern England and southern Scotland. The ongoing uncertainty threatens planning for events including the G8 summit and the football Champions League final between Barcelona and Manchester United, which takes place at London\'s Wembley Stadium on Saturday. Barcelona\'s squad flew to London on Tuesday, two days earlier than planned, due to the \"uncertainty\" caused by the volcano. European Union transport commissioner Siim Kallas played down fears that the situation could get as bad as in 2010, when thousands of travellers from around the world were left stranded. \"We do not at this stage anticipate widespread airspace closure and prolonged disruption like we saw last year,\" Kallas told a news conference. Iceland\'s Meteorological Office said activity at the volcano had slowed Tuesday, and an Icelandic crisis management official said the plume of ash had fallen from its peak altitude of 20 kilometres (12 miles) to two kilometres on Tuesday evening. When Iceland\'s Eyjafjoell volcano erupted last year, the ash plume arrived first in Britain before spreading across the rest of Europe. Many airlines were deeply unhappy at the time at being forced to halt their flights. Ryanair revealed Monday that last year\'s airspace shutdown cost it nearly 30 million euros (42 million dollars) and railed against the current closures. It said its one-hour verification flight in Scotland\'s airspace on Tuesday showed no visible volcanic ash cloud. \"The absence of any volcanic ash in the atmosphere supports Ryanair’s stated view that there is no safety threat to aircraft in this mythical \'red zone\' which is another misguided invention by the UK Met Office and the CAA (Civil Aviation Authority),\" the Irish airline said in a statement. The CAA no longer issues blanket bans on flights; instead, it identifies areas of high-, medium- and low-density ash and asks airlines wishing to operate in high- or medium-density ash to request permission to fly.