The British Retail Consortium is right about tariffs here

The BRC tells us that prices will have to rise upon Brexit given the current situation upon tariffs:

Supermarkets and their customers face £3.1 billion a year of tariffs on food and drink unless a free trade deal is reached between the UK and the European Union.

They do indeed get this right, unlike so many others:

In May, the UK published its new tariff schedule, which will apply from 1st January 2021 if a deal is not agreed. Under the schedule, 85% of foods imported from the EU will face tariffs of more than 5%. The average tariff on food imported from the EU would be over 20%. This includes 48% on beef mince, 16% on cucumbers, 10% on lettuce, and 57% on cheddar cheese.

They even get the solution correct:

The British Retail Consortium (BRC) has long been calling for a zero-tariff zero-quota trade deal between the UK and EU

Well, almost. Because they are calling for a deal. A deal would mean that goods flow between the UK and the remnant EU duty and tariff free. Which would be good, of course, as free trade is good. But a deal would also mean that the current tariffs against imports from the rest of the world would still be both possible and in place.

Meaning that we should be hoping for no deal. At which point we’re not going to do something as blindingly stupid as impose £3 billion of taxation upon our own wallets just because we like foreign food. So, we would go to zero tariffs. The absence of the deal meaning that we would then have to offer said tariff free access to the UK market to all comers. Or, alternatively, we’d not be taxing ourselves for buying foreign food from anywhere.

Or, to put it yet another way, we would adopt the only economically and logically correct form of trade management, unilateral free trade. As we did in 1846.

Having tariff free Danish bacon would also mean having tariff free Argentine beef. And? The problem with this is what?