Customs 101. A short thread. The application of customs controls is always a balance between facilitating trade and controlling it. The idea being that if you need the trade it is important not to stifle it. There are a lot of mechanisms you can use to mitigate this:

Inward processing, warehousing, free ports, etc. But at the heart of it all is that Customs must know what is coming into the country. What you are seeing at the moment is not French intransigence but a need to control the freight. Their balance is tipped towards protecting the

Single market. Its a legal requirement imposed upon them by membership of the EU. In other words, the single market is more important than the supply of British goods. The current "fun" with SMEs is just the beginning. The real issue is in the disruption of the complex supply

Chains and JIT. Once these complications set in, and the expense mitigating them is realised, then watch large businesses migrate across the channel. In short, ladies and gentlemen, it's a clusterfuck.