When ConservativeHome was born in 2005, disaffected Tory activists congregated in their thousands. The website became the most favoured place for any self-respecting Tory voter to hammer out his or her views, and its founder, Tim Montgomerie, a devout Christian, gained significant influence in Conservative circles. Often having a direct effect on Cameron's policies - particularly on marriage - Montgomerie's mobilisation of Tory support has forced the party leadership to keep a close eye on the site.
Montgomerie makes no secret of his profound social conservatism - and no one will be watching more closely, or voicing their disapproval more loudly, if Cameron fails to deliver on campaign promises. If Montgomerie comes to blows with Cameron, it won't be the first time he has battled his own party: he successfully fought Michael Howard's attempt to stop members voting in the leadership race. As he warns, Cameron "does not own" the party.