Fighting back against supermarkets

Warburtons thick sliced loaf (800g) is the product in question here.
We have a tesco and asda close to each other.
Currently as I post, asda are charging £1.39 for the warburtons bread, tesco are charging £1 - both put up the regular shelf price within 24 hours of each other.

Both were £1.37 - asda now charging £1.39 and tesco non offer price has increased from £1.37 to £1.39

None of the few local stores left have increased the price of their warburtons bread.
It is common knowledge that supermarkets move into an area then undercut local shops to become established, once they close or start to struggle, the supermarket raises their prices (tesco admitted doing this in our area on petrol, selling it 1p per litre more than their own store down the road, even though it was supplied from the same delivery, the reason given was "due to a lack of competition!")

More and more I am picking up on the fact that both tesco and asda in our area are increasing prices at the same time, often by the same amount.
Lurpak butter, both tesco and asda increased their prices of lurpak butter, both introduced a new salty version, again, at the same regular shelf price, both tesco and asda have recently increased their regular shelf price of lurpak butter to £1.60, again at the same time (This is a 60% increase in price since Feb 2011).

I am seriously considering lodging a formal complaint with trading standards and other relevant bodies regarding this practice. The competition commission should be on the look out for big businesses doing this as standard.
It's blatently ripping customers off!