Speaking to website IGN at the GDC in San Francisco last week, chief Phil Harrison offered a new explanation as to why 4 was not a exclusive. While 'slackness' on the part of former SCE president Ken Kutaragi has in the past been mooted, explaining the multi-platform move of both GTA4 and Assassin's Creed, the exec's reasoning was rather less controversial.

Pointing to the lead MS platform the has established, Harrison told IGN that it was likely the PS3 would simply be unable to build the installed userbase necessary for to turn a profit, given the rising costs and slow availability of stocks for the new console.

"I don't think PS3 has the install base to support Rockstar's investment in IV on its own," Harrison commented. With GTA4 due in October, and the 360 having already established itself as the number one system for the next six to twelve months, it seems Rockstar could have opted to hedge their bets by supporting more than one offering.

More soon.

By Luke Guttridge