Yesterday showed me that there is a need for some basic explainers. So let's do this as a morning exercise. There were three questions that stuck in my mind in the replies and I will tackle one of them today: so if we don't get frictionless trade, why do we want an FTA? (Thread)

First of all, some FTAs (in a broad sense) try to go further towards frictionless trade. A "Customs Union" eliminates tariffs altogether between the EU and a third country and establishes a common outer tariff. Turkey is in a CU with the EU.

Then there are the countries that are integrated in the Single Market. They apply the same harmonized rules as the EU. They also apply the "four freedoms" - free movement of goods, people, services, capital. That's Norway, Iceland and Liechtenstein (that's the "EEA").

Switzerland goes pretty much the same way, but the Swiss approach is mind-bindingly complex. There's more than a hundred agreements. Constant renegotiations to include more rules or update old ones when the EU updates stuff.

But the goal of the government is clear: none of that. No four freedoms, i.e. no internal market. No customs union. A "standard" FTA (there really is no standard FTA, but it means that the ambition does not go towards "Norway" or "Switzerland"). What does that mean?

An FTA does the following: 1) it reduces tariffs. That's good. But to benefit from the FTA tariffs you have to show that your product is a UK product. An FTA has rules for that: "rules of origin". You need to fulfill them - and prove that. So border checks for that, of course.

Why this administrative burden? Without it, other countries might transship their products. Think you are the US, for example. You have very low tariffs towards Canada because you have an FTA with them. You don't have an FTA with the EU. So...

... what would happen without rules of origin? All EU producers would ship their products via Canada (because Canada has an FTA with the EU) and they'd go to the US from there. Zero tariffs. That, of course, cannot be.

So benefit 1: lower tariffs, but with administrative hassle. Other advantages? Yes. Freely negotiated. For example: you can try to simplify some checks. Agree to use common standards in some areas. Have common standards for intellectual property. Easier visas for some.

However, FTAs don't go extremely far on rules and regulations. Because that's hard. Intrusive. You need to update them, so you would need common governance. You see the problem.

So as a summary: An FTA reduces tariffs and gives some limited benefits in other areas. It tries to resolve some concrete problems in trade (hey wait: you don't allow alcoholic beverages with that chemical, but that's a side-product of the production for X, can we change?).

But that's it. The ambition is not to eliminate borders. It can simplify some border stuff. Good. Better than not doing that.

Caveat (yes, I'm a lawyer) - in response to @AllieRenison, one of the passionate trade experts on twitter you should follow - this thread is meant as a basic explainer. An FTA is, in the end, a custom-made agreement between usually two parties. So...

If one of them wants to go further e.g. on services and the other agrees, it can be done. Trade is also an ever-changing field. So you will see that old FTAs differ from new ones. An FTA with country X will differ from that with Y.

If and where the EU and the UK develop ambition and agree on something - it's in. And all the talk of "we want CETA" or "this is not in EU-Japan" won't prevent that from happening where the parties agree.