The silliest thing about Johnson's antics with the kipper is that it perfectly illustrates one of the arguments the remainers have been making.

Our kipper supplier was based in the Isle of Man. To sell into the UK, since it is NOT a part of the UK, it has no choice whatsoever but to abide by the regulations the UK sets, unless it wants to cease trading with us. In precisely the same way, UK manufacturers will have no choice but to abide by the EU standards if they wish to sell to it. As far as that is concerned, it matters not a jot whether we are inside the EU or not. Of course, inside we can influence the regulations, whereas outside we cannot. In the UK we can, if we want, have different standards. But unless they are a strict superset of the EU ones, we can't sell to the EU.

A business could choose to have two manufacturing streams - an EU regulated one and an non-EU regulated one. Apart from the wastage arising from that, they would forever be having to prove they have not 'cross-contaminated' the streams, with all the costs that implies.