AV referendum: Cameron confronted by Huhne
3 May 2011 Last updated at 19:19 BST
Chris Huhne is said to have confronted the prime minister at a cabinet meeting, over the No campaign in the alternative-vote referendum.
Sources described a "bit of a bust-up" as the energy secretary "went for" David Cameron and Chancellor, George Osborne.
Both the Yes and No campaigns have criticised Mr Huhne for diverting attention from the main issues.
Nick Robinson reports.