For the supermarkets, it’s the public policy equivalent of a two-for-one offer – but with none of the attractions. While more than 500 pig farmers protested on Tuesday at Westminster about the poor prices they receive for their pork, the government was promising to act against retailers’ “irresponsible” alcohol price promotions.

This is a cocktail of populism and politics that the supermarkets have got used to swallowing. But still, it seems timed to stick in their throats. It is less than three months since the big food retailers were told to pay fines of tens of millions of pounds for allegedly colluding to increase milk prices – following pressure from the government and the dairy industry.