Tom Sutcliffe: This is a dynamic contest – even now I couldn't bet on the outcome

Halfway through the judging session for the Booker long list it occurs to me that our private room at the Garrick Club has become the tip of a dizzying inverted pyramid of human effort.

In total more than a human lifetime must have gone into the writing of the 140 odd novels we've considered, possibly years into their editing and publication, and months and months into our collective reading of them. Now the time-span has reduced to just two or three hours of voting and discussion, a cruelly narrow aperture through which a maximum of 13 books can pass.

Some, we already know, are at the front of the queue; before the meeting all five judges have submitted a list of 10 books we would like to see on the long list and a strong agreement has already emerged around four or five titles. But even now, at this late stage, the process remains surprisingly dynamic.

There are, of course, casualties that hurt. Every judge has a book they wanted to see on the list that didn't make it, and – if they're anything like me – will have left feeling guilty that their powers of persuasion weren't greater, or regretful that the long list couldn't be longer.

But there's no sense of settling for consensual second-best in our meeting. Our discussions crystallise a shared recognition of virtues that in some cases propel a novel from the back of the line to take the place of one that seemed assured of admission at the beginning of the meeting. I hope it goes without saying that every book on our list is worth reading once.

We've picked the ones we're eager to read twice and the fascinating thing now will be to find out which books best survive that process. What everyone wants from a Booker judge, I've discovered, is insider's odds. At the moment even I couldn't lay money on the result.