Was in M&S yesterdy and noticed all of the laundry products were 50% off including:
Non-bio tablets/liquid/Gel/liquitabs (as good as fairy IMO)
Colours (as above)
All fabric conditioners, including the lovely Wild Hibiscus & Vanilla
And many others including the Wools, Cashmere and Silks non biological concentrated liquid for 99p which is excellent for stopping problems with washing delicate items.
Here's the link for all the info about the products:http://www.productsafetyinfo.co.uk/ClothesCare.htm