The following article appeared in the Harrow Observer (online) on the 18th September (2008):
Police investigate school's alien invasion
Children from an Edgware school were made to believe aliens had landed in their playground by teachers and police. After spending this morning bewildered by the unusual hoax, pupils from Stag Lane School in Collier Drive, quizzed police officers brought on to the site during a press conference to make the event seem more realistic. Forensic examiners had earlier analyzed an 'alien claw' they had 'found' on the site.
The aim of the day was to stimulate the children's minds and help develop their story writing skills. After lunch the pupils were informed by the school's headteacher Elena Evans that it was all a stunt.
Source: Harrow Observer