With each class we talked about how every superhero is thought up in the imagination of its creator, and that what I was looking for was to create a superhero team with their help, like The Avengers, made up of lots of different heroes with different powers, that together made a formidable team. I explained that what I was after was their character's origin story - the tale in which an otherwise ordinary person obtains their powers, and what then made them want to do good with it. We could then think about what their character would dress like, or look like, and what superhero name would they adopt.
To give them an idea of what I was after we developed one character as a class with each group of children. There were some brilliant suggestions, such as pilot called Flash Rogers who spies a hero battling with a villain from his plane and flies down to help, only to discover the hero is badly injured and passes on "the King's Seal" to Flash so he can turn into Sonic Boom Boy. In another class we had an Antarctic scientist, there to study penguins, fall down an icy chasm where he lands amongst blue glowing ice. This gives him the power to turn into a man of ice and rock with the ability to shoot freeze rays so he can defend the North and South Pole - he was The Incredible Icer (and, oddly, he dressed like a baseball player).
The children were then left to write their own heroic origin stories, and it was really pleasing to learn that some of the boys who would sometimes struggle to get their ideas down on to paper were rattling off line after line of story, with one boy giving up some of his lunch hour to do more.
Poulner were also kind enough to let me do a book signing at the end of the day in their library which was very well attended. Thank you to all the staff and children who looked after me, particularly for the home-made cake!