Why Cameron hates AV

There is analysis by John Curtice (usual provisos apply, of course) that suggests that the Conservatives would have had less than 75 seats after the 1997 general election if AV had been in operation. Further, it looks as if, under AV,  the 2010 general election would still have produced a hung parliament, but with Labour as the largest single party. Accordingly, Nick Clegg would have been committed  to negotiation with Gordon Brown (or Harriet Harman) afterwards. It is surprising that more Labour MPs have not joined Peter Hain and Dr Hywel Francis on  the bandwagon.