Cornerstone's president is Lincolnshire MP Edward Leigh and it's chairman is John Hayes, MP for South Holland and the Deepings.
As Cameron attempted to tell the public that he wanted the Tories to be on the centre ground of British politics, he was privately pandering to the right-wingers who are chuffed with his performance to date.
After all, Dave flip-flop caved in to his own right-wing's obsession with Europe by agreeing to leave the mainstream EPP grouping. The price the Tories are paying is isolation in Europe.
And he did a spectacular u-turn on his 'no more grammars' policy, by agreeing there could be some new grammar schools, but only in certain areas.
And then inserting a line in his speech yesterday promising a 'grammar stream' in every school following pressure from Edward Leigh and Cornerstone.
Well, it's worth noting that Cornerstone recently called for the NHS to be replaced by a system of compulsory private healthcare.
Right-wing Tory MP for Northampton, Brian Binley, who met with Cameron yesterday said:
I don’t have to tell you that I am considered on the right of the party and I’m delighted that our views, our political concerns are being considered very seriously in the policy review group.UPDATE: Links added to to Independent story Right wingers step up pressure on Cameron and Daily Mail story Tory right reopens battle on Grammars.