AN investigation was launched this week into how national test papers, completed by more than 200 pupils, were accidentally dumped in a skip and destroyed. The 242 Year 9 youngsters from Hummersknott school in Darlington, County Durham, wee devastated when they learned that papers in their key stage 3 English tests ended up in a landfill site after a teacher mistakenly left them in a corridor. It has not yet been decided whether the pupils must retake the tests.