Part of the pre owned deal of the week. I expect this will get very cold as people tend to hate pre owned games instinctively, but its still the best price around and you DO have the right to dispute the game disc you receive when purchasing it so that you can get one in pristine condition. Ive done it a few times as the staff generally try to get rid of the poor condition ones first.
They also had others in the deal:
Darksiders - Both consoles £24.95
Race Driver GRID - Both consoles £9.95