Volcanic Ash Forces UK Flight Ban Extension All flights in and out of the UK have been grounded until 1pm Friday at the earliest because of a huge volcanic ash cloud that has hit the UK. Some flights from Northern Ireland and the Western Isles of Scotland between some Scottish cities may be allowed between 0000 GMT and 1200 GMT, the National Air Traffic Services said. David Harrison, safety officer for NATS, told Sky News he could not say when the ban would be lifted, adding that it was "really, really important to be cautious about this as I do not want to give anyone the impression... we we will get things back to normal quickly". All UK airports - including Gatwick and Heathrow - have been closed causing disruption for around 300,000 UK passengers :: Watch Britain Grounded - a Sky News two-hour special programme on the effect of the volcanic ash cloud Many European airports have also been closed as the cloud of ash sweeps south and east of Iceland. Flights across Northern America are also affected. Ryanair has cancelled 600 flights and says it will not allow aircraft to take off before 1pm tomorrow. NATs had earlier said the flight ban would last until 7am tomorrow. Airports are urging travellers to contact their airlines' websites to check whether their journeys are affected. Nats took the step to ground all flights as ash from Iceland's Mount Eyjafjalljokull volcano arrived in British airspace. The air traffic control company said