Two recent headlines might make you pause for thought, they are: "Ebook sales pass another milestone" and "Ebook piracy 'is colossal threat'". How can it be, you might ask, that the fastest growing segment in the US books marketplace (and probably the fastest growing in the UK, too) is also being undermined by "colossal" piracy?

As I wrote on FutureBook last week the Piracy Defence is a useful one for publishers to propagate. It is no surprise to find the Sunday Times taking up the cudgels, closely followed (pirated, perhaps) by the London freesheet Metro. The reports state that in the past week alone the PA's Copyright Infringement Portal has received 831 infringement reports and issued 2,194 takedown notices. More than 32,000 removal orders have been issued this year.

Actually, if 32k takedown notices have been issued over the past 15 weeks, then 2,194 in one week represents little or no growth in piracy.

Still, author David Hewson is surely not wrong when he says: "It’s colossal. It’s really got big over the last year, I guess because so many people are buying ereaders. Everything I have ever had published is out there now. We all saw the damage this did to the music industry. It isn’t a bunch of Robin Hood geeks – it is very organised. You can call it file sharing or piracy or whatever, but they are thieves."

Neither is Ian Hudson, deputy chief executive of Random House UK, wrong when he reveals that the company employs a team of 10 anti-piracy monitors. "Three years ago we didn't spend anything on anti-piracy. Now we're spending many tens of thousands of pounds on it."

His words will surely be welcomed by Little, Brown publisher David Shelley who did not win much support at the London Book Fair's digital conference last week when he first raised the issue of piracy, and the escalating costs of combating it. The influential US blog Publishers Marketplace labeled Shelley's remark the "silliest" of the fair, while publisher-phobic blogs took to their keyboards to denounce the copyright fetishists.

There should be no surprises here. As the PA's chief executive Richard Mollet writes in his blog Reflections on LBF: "There will always be our sector's equivalent of 'deficit deniers' -  people (usually academic self-appointed copyright experts) who tell us that there will not be a depletion of revenues from infringement, or if there is then it is the fault of the creative sector itself. They believe that copyright is the cause of infringement - a position which owes more to rhetoric than to evidence."

Publishers are damned if they do, and damned if they don't. If they don't fight piracy, and it grows to Napsterish proportions then they'll be accused of having behaved like ostriches. If they do fight it, then they'll be expected to absorb the costs as just a new overhead.

The problem publishers face is convincing the 'deficit deniers' that their actions are wise. That a 10-strong team scouring the web is really a worthwhile investment on behalf of their authors.

At Frankfurt's Tools of Change conference 18 months ago trade publishers caused a stink when they decided that a panel on piracy, following research by Magellan's Brian O'Leary was sending out the wrong signals: that piracy could actually boost sales. O'Leary retorted that the consumer publishers should fund proper research or at least join his research panel: but as far as I know this has not yet happened.

And at the moment the evidence is all pointing in the other direction. Sales of e-books are rising faster than anyone's expectations, on both sides of the pond. Kindle and Nook users are buying more, while digital hits are driving rather than undermining print bestsellers.

The evidence of piracy is clearly very real, but the impact of it on sales remains a puzzle.