Right now, multiple UK supermarkets (Tesco and Sainsburys) have a price match system, where selected products cost the same as at a budget competitor - Aldi.
This means, for example, a 400g tin of Chopped Tomatoes cost the same at all 3 supermarkets (39p as of writing). However, the price was recently increased at Aldi (from 34p), meaning the price went up everywhere.
I'm interested why this doesn't fall afoul of any anti-cartel / anti price-fixing laws. What's the difference between a price match and price fixing?