Half term holiday flights on knife edge: Family breaks under threat as Met office warns ash cloud could blanket Britain

By RAY MASSEY Eruption: A photographer captures the volcano exploding out of the earth Met office says a dense layer will cover the UK on FridayCivil Aviation Authority says the number of flights could be 'rationed'National Air Traffic service warning of further chaos todayRyanair warned after saying it could fly its planes through the ash The holiday plans of hundreds of thousands of Britons