So is it getting a sub-100 majority that they fear? Yes, that would make life complicated, but not insurmountable. It would make it difficult for the Blairites to push through the choice agenda. A good enough reason for conscientious Labour lefties to stay at home methinks, even ignoring Iraq.
If enough Labour voters stay at home or switch to the Liberals, the Tories might realistically get a bigger percentage of the popular vote (assuming they have got their own vote out with a combination of dog whistle issues and a popular desire to wipe the smirk off Blair’s face.)
The Tories could get 32% of the vote, Labour 31% and the LibDems 25%. Leaving Blair arguably with no popular mandate, but a working majority of 60+ seats. Its not that far-fetched, Howard would scream blue murder, Blair would have to resign in favour of Brown.