It might be, if reports circulating this morning are to be believed, that the best reason for watching the next Bourne movie has left the project. While we quite liked director Doug Liman's The Bourne Identity, it was Paul Greengrass, for our money, who gave the franchise a huge jolt with his Supremacy and Ultimatum sequels. And as a result, whenever the fourth Bourne movie was mentioned, Greengrass' name wasn't far behind it.

Greengrass is currently putting the finishing touches to his next movie, Green Zone, where he's reunited with his Bourne leading actor Matt Damon. Damon and Greengrass had both expressed interest in revisiting Bourne, but it always appeared to us that each was dependent on the other being involved.

And right now, Greengrass may not be. For it's been reported that he's quit the project, according to The Playlist. The site reckons that this happened around a week ago, and there were a couple of points of friction between Greengrass and Universal that led to it happening.

Firstly, there's the issue of writers. Two drafts of Bourne 4 have been turned in so far, one by George Nolfi, and the second by Josh Zemuter. While, apparently, there's been little favour for the former, Greengrass wasn't consulted, it seems, about the employment of the latter.

On top of that, there's the issue of Green Zone, which has included the kind of furious - and expensive - reshoots that Greengrass undertook on The Bourne Ultimatum. That's taken the budget for the film closer to the $150m mark, something that's not made Universal particularly comfortable. The studio had seen Green Zone as a smaller project for Greengrass to tackle between Bourne movies, and it's now seen the price rise to the point where it could have made Bourne 4 for the same money.

The Playlist has the story in more detail, but right now it seems, Greengrass is off the project, and that means it's quite likely that Damon could follow. That would leave Bourne 4 dead in the water. However, it's also noted that this may be a temporary parting of the ways, and things may yet come back together in a few months' time.

The one thing that looks certain in all of this is that the 2010 shoot for the next Bourne film is now in jeopardy, unless something can be sorted out quickly.

Here's the story at The Playlist.