In February 2010, just after Tony Blair appeared at the Chilcot Inquiry, ComRes published a poll for the Independent that asked voters if they think Tony Blair should be tried for war crimes. 37% voters thought he should, whilst 57% of voters thought he should not.
As a percentage of voters on the electoral roll in 2010, this means that 17 million voters wanted Tony Blair placed on trial for war crimes. Those in favour were predominantly the young (those under 35) and those from northern or poorer parts of the UK. Those who were of mind not to put him on trial were mostly the elderly, southern wealthy types. You can see the data for yourself (here).
If you want to geek out on why polling is a science not an art, and how we are able to recalibrate the polling %s into numbers of actual voters, then please follow this link (here).