The answer is to shop local if you can. If there was a shortage then my local farm shop and the market stalls in town would be empty but they're always full of stuff.
The supermarkets are constraining their stock because they import as cheaply as possible and costs are increasing. If the supermarkets have to spend more due to rising costs then they'll buy less to still make more profit.
They'd rather have empty shelves than risk losing that profit in excess which ensures the shelves stay full. They've put most prices up far beyond inflation anyway so they're absolutely quids in.
So yeah we can all blame events like Brexit and get into politics but a good question is how did Tesco double their profits last year to £2.5bn if they have nothing to sell?