Read not on the label by Felicity Lawrence and you’ll probably change your shopping habits.
Basically you get what you pay for and if a shop is cutting prices, where are they making their margin? In the case of Lidl and Aldi, they appear to make their margin by cutting the number of staff required because of the rough and ready service. Tescos on the otherhand screw everyone else in the supply chain, and do you really want to be eating food produced by people upset by the way they’re being treated? (Which is also why you should never be rude to a waitress or chef before or during a meal.)
That said, I don’t mind them undercutting EAs but I do try not to shop there.