Found this Morrisons at Colwick, Nottingham last week.
I saw Mirror's Edge (for £6 on PS3 & XBox 360) and others games for various formats from £5 in a promotions basket near the entertainment section.
Other HDUK members who have gone for this deal have also found Fallout 3 as well as others in the basket too.
There are a few to choose from on either PS3, XBOX360, Wii, DS, PS2 or PC.
(Apologies if this is already posted - could not find it though)