1/5 Under WTO rules, the UK is expected to be able to check, measure and control the value and volume of goods crossing our borders. This is to ensure we know what tariff to apply to imports and how to calculate tariff rate quota.
2/5 if we do not measure, check and control the volume and value of goods coming into the UK then we will have disputes all over the place about incorrect tariffs being applied to stuff we buy.
3/5 if we are not checking the standard of goods coming into the UK then whatever we make from those parts and raw materials will not be able to be checked for Country of Origin to ensure they are of sufficient standard for the final product. Food, cars, manufactured goods etc
4/5 say we import cheap low standard brake parts and fit them to a brake assembly that is then put onto a car. If we cannot guarantee with a paper trail all the parts used are of sufficient standard for the target destination of that car then we wont be able to export it.
5/5 UK proposals for customs checks is simply undeliverable. The promised versions of Brexit were all undeliverable and now it looks like all our exports are going to be undeliverable to our customers around the world too.
What a mess.
What a mess.