THE UK and the EU are now like two trains that sat together in the station for a long time. Then when the Brexit signal was given, they began their journey, initially on parallel tracks but now curving in different directions.

That divergence has surprised many observers, but it became inevitable when London, in its final deal with Brussels, opted to put sovereignty ahead of cooperation and market access.

The effects of this policy decision are becoming more obvious as the UK increasingly goes its own way. Over some of these decisions the inevitable question is whether practical cooperation would have been better than political dogma. But compromise will never be on the agenda of any government with a large majority at Westminster.

This will ultimately test which train is on the right track, but before the answer is known it will be a bigger test of whether devolution really can deliver different outcomes for the different UK regions.

A small, but good, example of being on different tracks is what has happened with geographical indication (GI) products. Those approved and in place before December 31, 2020, when Brexit formally happened, remain part of the original EU scheme with all the national and global protection that offers.

The UK could have opted to remain part of that scheme, but instead opted for a home-grown scheme. The first product has now been approved. It is Welsh lamb produced on specified salt marshes on the Gower Peninsula. This will be a GI product in England, Wales and Scotland.

But it will not be recognised in the EU or indeed in Northern Ireland. There, thanks to the complex protocol the government accepted to avoid any adherence with EU rules, the existing EU scheme remains in place. Even when it comes to a simple quality scheme, the border the government created down the Irish Sea is the driver of policy. Time will tell whether a regional UK scheme can have any global impact. But the more fundamental question remains what was the point of breaking away from an effective scheme for the unknown?

A ban on live exports is now UK government policy, reflecting its determination to prove that Brexit is worth the commercial pain it has brought. This is further evidence of the gulf between the government and rural communities, which would have liked to have seen it pursue policies likely to have a more immediate impact there. This is a cynical ploy targeted at an urban electorate that, for example, was never concerned about bovine TB until it affected a pet alpaca imported from New Zealand.

More could have been achieved for animal welfare by cracking down on non-stun slaughter and demanding that imports meet the same standards as the UK. However in an era of social media and sound-bites politics, policy is made for today's headlines rather than the long term. This is certainly an area where the UK is on a different track to the EU. Many urban voters will see that as a simplistic argument in favour of Brexit, deeming the problems it has bought a price worth paying for such a totemic policy gain. That is exactly what politicians wanted, and they have played that hand to perfection.

These are just skirmishes in a larger battle. That is set to come over gene editing – changing the genome within a species – and genetic modification, where other species' genes are introduced. The government in London wants to commit as quickly as possible to gene editing. It rightly believes that over this, and indeed GM, the EU has a track record of being swayed by a minority.

That is entirely correct, so while the EU remains ultra-cautious in its debate around this issue, London wants to get going as quickly as possible. This will open a big policy battle, meaning those two trains have reached a point where the lines are curving steeply in opposite directions.

That is acceptable, but the government must fully think out the market implications if it opts for policies radically different to those of the EU. It could find technicalities used to close it out of its biggest export market. Those would counter the gains from gene editing.

This and decisions on support will further strain devolution as London accelerates the demise of a British agricultural industry, built on the different countries that make up the UK pursuing common goals in farming.