THIS WEEK'S Conservative party conference was an exercise in papering over the huge Brexit cracks in the party. These have not gone away and no matter what deal is reached with Brussels, they are likely to eventually split the party, as happened over the Corn Laws and Europe in the 1870s.

Labour is no better off, with its Momentum activists threatening to deselect moderate and long serving MPs. Whether this leads to the creation of a new centre ground party only time will tell, but farmers have enough to worry about without speculating about mainstream politics.

As far as farming is concerned, there are three key Brexit areas. These are easy to say, but a big challenge to resolve. Top of the list is support to replace direct payments. That is in the hands of the government in London, and the building blocks are in place.

Next comes regulation and all the changes needed as we move away from years of regulation, that ensured conformity across 28 EU member states. Now the UK will have to make its own policies, and that task is still on the drawing board. The challenge is to make it less bureaucratic, but whether that can be a Brexit dividend is doubtful.

The big one however is the market, and this is what is tearing the Conservative party apart. Over the coming weeks we will hear lots of terms bandied about on market access and it is worth understanding what they really mean, without political spin attached.

The customs union is what we have now. This is the basis of the single market, which means a product made in Lerwick can be sold in Luxembourg with no customs or demands for different standards to be met. Securing the single market was one of the biggest achievements of the UK when Margaret Thatcher was prime minister, but it has been written off by today's Conservative party. It applies to the movement of goods, services and people and the EU has said it will now allow the UK to cherry pick the parts it wants.

When people voted to leave the EU in 2016, no-one told them this would mean leaving the single market, but this is now a core government principle. Politics are overriding economics in both London and Brussels, despite both sides knowing a deal makes sense.

The term that has come to the fore is Canada plus, or even plus, plus. This is a reference to the free trade deal the EU has in place with Canada, known officially as the Comprehensive Economic and Trade Agreement (CETA), which allows reduced or no tariff trade between the EU and Canada. This is a complex trade deal, with tariff decisions taken on a commodity by commodity basis; it took seven years to agree.

CETA has been in place for a year, and has brought about a small increase in overall trade between the two blocs. This is far removed from a single market or even universal free trade, but it leaves both parties free to do their own thing with other countries. Proof of this is that Canada this week tied up a much more important free trade arrangement with the United States and Mexico, replacing the NAFTA (North American Free Trade Agreement) scrapped by the Trump administration.

The CETA deal is based around a trade model that aims to expand a limited trade between two trading blocs. Tariffs remain part of the equation and there is limited acceptance of common standards in areas such as food. In a UK/EU context it would not reduce customs checks, allow companies to operate a 'just in time' approach to stocks, nor avoid a hard border in Ireland.

The other option is membership to the European Economic Area (EEA), which is a halfway house between the single market and CETA. This is effectively a single market in goods, services and people but does not tie non-EU members to the CAP or the Common Fisheries Policy. Switzerland has a separate single market deal with the EU, but Norway, Iceland and Lichtenstein are members of the EEA.

This would be the easy option for UK agriculture, allowing market access without the CAP, but it is a deal too far for Tory Brexit supporters. It makes economic sense, but that lost out in today's Conservative party when Boris Johnson, as foreign secretary, responded to concerns about the impact of Brexit on jobs by saying 'F*** business' for daring to question politicians.