Having let slip themselves that the game will support the PlayStation Move peripheral, it seems Sony's decision to implement motion controls into Gran Turismo 5 is the reason for the game's lengthy delay.
According to a "source close to Sony", trade site MCV reports that a decision by Sony to put both motion controls and 3D - which we thought they already had - into the final version of game is the reason Gran Turismo, which should already be out by now, is not.
Far from ruling this out, Sony says "We will be announcing further details of Gran Turismo 5 in June in Los Angeles during the Electronic Entertainment Expo. Until that time we cannot comment on rumour or speculation."
So, there's a good chance that what you just read above, you'll be reading again in a few weeks time!