Here's an early comment that says it all really:
The whole point is they don't want anything to come out that makes them look bad. The whole country knows that the war was illegal and that we simply bowed the knee to our American masters when they called. The more they try to hide things, the more our worst suspicions gain ground. It may well be that they were all damn stupid. But unless they put everything out into the open, the public will continue to believe the worst, whether founded or otherwise.
If they have nothing to hide, then they have nothing to fear from a public, all-encompassing enquiry, have they?