Part crowdsourcing, part competition, the Guardian is asking readers to help them analyse financial structures set up by the former prime minister Tony Blair, which involve artificial partnerships.

The new project is similar to that run by the newspaper during the MPs expenses scandal, when readers where asked to look through and flag up points of interest on expenses claim forms.

This time there’s a competition element too: readers are asked to trawl through relevant documents and make comments and annotations. Featured contributions will be credited and readers will have the chance to win an origial cartoon by Steve Bell (deadline is 6 December).