"Make no mistake," said SEGA this week, "if one quarter of the people that usually pirate [Football Manager] switch to purchasing Football Manager 2012, the sales of the game worldwide would more than double." That was the eye-opening statistic used to justify Football Manager 2012 requiring Steam to play. In other words, more than 80 per cent of people playing Football Manager are doing so with a pirated copy.

Is PC piracy really that bad?

"Piracy levels, depending on country, range between 40 per cent and 80 per cent," Reinhard Blaukovitsch from Sony DADC, the company responsible for SecuROM, told Eurogamer as part of an investigation into the true impact of PC game piracy. That means that between 40 and 80 per cent of total copies of a game being played are pirated. "The commercial value of global software piracy is growing by 14 per cent annually."

In January this year, UKIE - a consortium of UK game publishers - revealed that for every one game sold, four were being pirated.

"We looked at quantifying what the real losses are," says Christian Svensson of the PC Gaming Alliance and Capcom, "and it's incredibly hard to do, because you end up having to do a set of cascading assumptions that you have no real ability to validate in any meaningful away."

"It's impossible to know how bad piracy is," agrees Michael Pachter, Wedbush Morgan analyst, "but it's pretty bad. [Clarification - Michael Pachter heard from Ubisoft that piracy rates were as high as 90 per cent per title.]"

Hard facts and figures are difficult to come by, then. Eurogamer asked various publishers for statistical data and input, but our enquiries were fruitless. Sony DADC cites "various sources". Other companies we spoke to mentioned research by companies like the ESA and DFC Intelligence; others monitor BitTorrent statistics; and others use data provided by game sellers. And it's not uncommon to use them all together.

"Let's turn the discussion away from sales to how many copies are sold legitimately versus how many copies we see downloaded illegitimately," Svensson continued, "irrespective of how many could actually be converted to a legitimate user. I would say that at the low end of the threshold - and it varies greatly from territory to territory and brand to brand. Bigger brands see higher levels of piracy - it tends to be 50/50. That's the lower end."

"At the higher end you can see 90 per cent illegitimate usage to 10 per cent legitimate," Svensson says. And they're not, what he calls "victimless crimes". He says Capcom had support calls from people playing pirated copies of the game. "There's a dollar cost to that. They're not even aware of what they're asking being wrong," he shrugs, "they're not aware it's theft. It's a cultural issue. And you'll find that the sensitivity to it or against it really varies a lot, a lot, from country to country."

"Ubisoft told me that their PC game sales are down 90 per cent without a corresponding lift in console sales." Michael Pachter, analyst, Wedbush Morgan

For some time, publishers have tried to protect their games from the rope-worn hands of pirates. Elite used the Lenslok, a device through which a corrupted image of a number on a screen could be correctly viewed. Some publishers even drilled holes into floppy disks at known locations to throw pirates off. Then there was the flicking through manuals to locate specific words and sentences based on coordinates given on screen. These days, companies opt for DRM - digital rights management.

But does it have any effect on piracy?

"[There's] no public data to suggest that DRM works," says Pachter, "but the fact that more companies are imposing it strongly suggests that they believe it works."

Svensson is convinced that it does work. "Through the use of DRM, a publisher can meaningfully improve profitability on a project. But I would also argue that it has as much to do with an ecosystem where content is not unilaterally available, which means that DRM is really only effective if a broad number of participants are actually employing it. The reason being that the habitual PC pirate, or pirate of any platform, if there's one piece of content that they can't pirate, that's OK, they're going to move on to the next piece of content they can."

"There's some sort of element of solidarity being required amongst publishers to really have those investments. And I say investments because it does take time and money and effort to implement DRM in a meaningful way and minimise the impact to the consumer. What you've asked is a very thorny question. The reality is, it would take converting three per cent of those people who pirated that game to be paid users - a very nominal amount - to meaningfully impact the actual revenue and profitability on the title."