This, incidentally is quite right. The discipline of the Tories has been remarkable so far – especially as they must be bitterly disappointed with the election result, and more than a few will have major complaints with how the campaign was managed.
As a basic negotiating point, you should only ever make one ‘final’ offer. If Cameron were to offer any more than is already on the table it would look extremely weak. If the Lib Dems really are too prejudiced even to agree to limited and conditional support for a minority Tory administration, then let them stagger into the poisoned embrace of the Labour party.
With 307 MPs, the Tories would be a staggeringly strongly placed opposition. The Lab-Lib-SNP-PC-SDLP-ALL-IND-GRN alliance would need to have nearly all its MPs at Westminster all the time to avoid being ambushed. As few as 10 rebels would be needed to sink a bill even if the full complement turned out. It would be a procedural nightmare, and provided the Tories played it cleverly, they could maintain the moral high ground throughout.
It wouldn’t take much for a fatal break-down in relations, and that would lead to a fresh election. One of the points that the Tories tried very hard to make during the campaign was that the only way to get rid of Labour was to vote Tory. There could hardly be a more elegant proof of that than a grand coalition of every other party in the Commons to keep them out of office.