Realistically in order to prosper the UK needs to join up as part of a "greater NAFTA" trade bloc. But the UK no longer has anything that the USA needs so they'll have to make major concessions to get a deal done.
I realize it's an outdated stereotype but man it says nothing good about America when the UK won't join up because it would compromise the quality of available foods.
When you're starving you eat what's available regardless of how appetizing it looks. The UK isn't starving yet, but how long can they hold out? And has NAFTA ruined Canadian or Mexican food?
Apparently I was being a little too subtle. I meant starving for free trade relationships and participation in a larger economic bloc, not literally starving from lack of food. The point is that UK will have to join up with someone else eventually; they lack the scale to go it alone.