Our lead story in the second show daily of the London Book Fair follows up on Little, Brown publisher David Shelley's comments at the pre-show digital conference that fighting online piracy was now a significant new cost faced by publishers and one of the reasons they couldn't simply raise digital royalty rates as some agents would like them to do.

"E-books can be pirated as easily as MP3s," Shelley said.

Some in the audience clearly didn't believe a word of it, as was evident from the applause the author Lisa Gee got when she claimed not to be "afraid" of piracy. Delegates I spoke to afterwards were also pretty skeptical. The words "bogus" and "ruse" were muttered by some. Mike Shatzkin told me that no publisher he knew of had done any research into the commercial impact of piracy and therefore it was a waste of money trying to contain it.

Furthermore, in a recent submission to the Hargreaves Review of IP, even the Publishers Association conceded that piracy was not yet a big issue for publishers. It looked at two titles The Confession and Jamie's 30 Minute Meals and concluded that P2P infringement represented a "mere 0.05% of sales".  "It would be wrong, therefore, to overstate the extent of online infringement for published content at present," the PA said.

Nevertheless Shelley was backed by both Faber chief executive Stephen Page, and the PA's chief executive Richard Mollet. Both said online piracy was a rising, and somewhat unknown cost. Mollet said: "It's obvious that as the digital market grows so will the degree of digital infringement. To keep up with the pace of change, publishers, and indeed all of the creative industries, will have to spend more money."

Whatever the merits of the argument, I can see why publishers would think it was smart move to raise the spectre of the online pirate. Gee might not have to worry, but if the sales of her titles fall as a result of piracy, then she is going to be looking at her publisher to resolve it. As Shelley commented, a big publisher can fight this an individual such as Barry Eisler cannot.

But the main point, I think, is that it is a very clear message. There are few more emotive issues than author pay, but piracy is one of them. It can sometimes be difficult for publishers to explain why their cost base is not reducing because of digital (VAT, managing meta-data, copy-checking) but none of these reasons are half as memorable as the piracy defence. Not only is there an implied cost in fighting it, but it also shifts the onus of blame away from the publisher towards the robber pirate.

But it could easily back-fire. As one agent said if publishers are going to use the piracy defence then they need to be able to prove that their actions are working and that piracy is a real threat: "I would love to know what publishers are actually doing to fight piracy. I can't imagine any publisher is together enough to combat it."