Sources

I watched the Panorama programme yesterday and i decided to share this to everyone. The reporter pointed out clearly that we, as the consumers, are actually more worse off when the supermarkets do the price war. The supermarkets put the price up for some items and then say it's on the promotion but it turns out that it's actually the original price. Moreover, they use some kind of psychological pricing so consumers can't really work out that they have to pay more for the items. 

http://www.bbc.co.uk/iplayer/episode/b017yvfp/Panorama_The_Truth_About_Supermarket_Price_Wars/

Although the big 4 supermarkets now seem a bit more quiet than in October. But I really think consumers should all know about what the deal and discounts really are when they shop at the supermarkets