The Last Guardian is in "earnest" development, but the game is not a priority at SCE Japan Studio, according to Team Ico head and creative director Fumito Ueda.
"It's under earnest development," Ueda said of The Last Guardian. "However, SCE Japan Studio, who's working on The Last Guardian, also has titles like Puppeteer and Knack, and those are only the ones currently announced. Those are taking priority right now."
The Last Guardian has made "slow progress" for years. Sony senior vice president of product development Scott Rohde said during E3 2012 that the game will ship "when it is absolutely ready." He also said Sony has no deadline whatsoever for the game.
The Last Guardian was formally announced at the 2009 Electronic Entertainment Expo.