It was a killing that jolted a generation of youngsters across the world, but now a jury has cleared an unpopular teacher of murdering his school's much-loved headteacher.

The venue was the Owl Court, specially convened at Dereham Sixth Form College yesterday for a Harry Potter-themed charity fundraising day, and the defendant was Professor Severus Snape, who admitted killing Hogwarts' principal Albus Dumbledore but denied murder.

Law students assumed the roles of defence, prosecution, judge and jury, and cross examined witnesses including Harry Potter, and cited legal precedents, explained the requirements of each charge and produced evidence culled from films and J K Rowling's books.

The jury found Prof Snape not guilty of murder, but convicted Madame Lestrange of torturing Hermione Granger and murdering Sirius Black, and found Lord Voldemort guilty of murdering Harry Potter's mother Lily.

The exercise allowed the would-be lawyers to apply their legal skills to court room scenario that used cases familiar to their fellow students.

Alex Williams, vice-chairman of the student council, said: 'Everyone was serious about it and it was a good way of learning how to prosecute someone.'

The day also saw Chris Rankin, who played Percy Weasley in the films and is the son of soon-to-retire teacher Marilyn Rankin, answer questions about his experiences on the set of the most successful film franchise in history.

Mrs Rankin said: 'The event sprang from the A-level law students' need to understand court procedures and to know and to be able to reference significant legal rulings, so this was all grounded in the curriculum but was end of term levity putting the Harry Potter villains on trial.'

The day also saw students make broom sticks which they later raced, and don Harry Potter costumes to raise money from bemused members of the public in the town centre.

Organisers more than doubled their fundraising target to collect �217 for Brain Tumour UK.