Tariffs are blunt, costly and ultimately a self-defeating policy.

This is particularly so when they are delivered in knee-jerk Trump style, rather than strategically targeted and thought out. The latest threat from the US to car makers in the UK has created new concerns for the farming lobby.

Leaders of the UK farm unions, meeting in Northern Ireland last weekend, highlighted their fears as the latest Trump tariff plans emerged in Washington.

Thankfully the prime minister, Keir Starmer, has said that along with the EU he is ready to retaliate against the US. For the record, what Trump is doing is not only economically illiterate – adding to consumer prices and inflation while undermining economic growth – but is illegal under the World Trade Organisation rules. The US was to the fore when these were established to prevent just what Trump is now doing.

Then as a major trading nation the US believed it had everything to gain from free and well regulated international trade.

The farming lobby has reacted around the potential implications for the industry if the UK buckles to US pressure and offers either concessions or seeks to rush into a free trade deal. A trade deal is an unlikely prospect. Politicians and officials would find it hard to negotiate with the US in any expectation that good faith would be displayed by the Trump administration. It has no respect for other countries and no respect for the rules governing world order.

In short a deal could be done and then it could be torn up at the last minute after the UK offered concessions, forcing it to decide between no deal and a bad deal. Trade deals take years not months to negotiate, although if one side rolls over that may not be the case. The EU agreed a trade deal with the Mercosur countries of South America 20 years ago, but it has still not been ratified by member states.

This is because of concerns about the impact on agriculture and because of concerns about environmental standards, particularly in Brazil.

Much as the UK, in theory, wants a free trade deal with the US it is not going to happen quickly and it will not be a response to the threat of tariffs. Trump would love to separate the UK from a pan-European position on tariffs.

He is a firm believer in the principles around divide and rule. Starmer is too wise to fall into this trap, knowing that while a deal with the US might be beneficial this would not be the case if it were delivered at a cost to the UK’s trading relationship with the EU.

He also knows, even if he cannot say it, that deals cannot be done with someone who daily highlights with some pride his bad faith and belief he is above the international rules of trade and diplomacy.

This does not mean the farming lobby is wrong to raise concerns. It is justifiably cautious about the actions of a government that has not only done nothing for agriculture, but which through the budget embarked on policies to damage the industry.

There is a lack of faith that the Starmer government is to be trusted when it comes to doing the right thing for agriculture.

The farming lobby knows that if it comes to the crunch and trade concessions are on the table there is no certainty the government will do the right thing for agriculture. We know all too well the issues the US resents when it comes to trade in agricultural and food products. These include some GM techniques, the difficulties of securing assurances around the use of hormone growth promoters, environmental standards and the headline grabber of chlorine washed chicken.

It is easy to see a situation where Trump offers to go easier on UK tariffs in return for concessions. He would love to force the UK to accept US food standards as a signal that others in Europe are wrong to reject them. This would be bad for UK farming and consumers.

It would also destroy the free trade arrangements we have maintained with the EU, as our biggest market, despite Brexit.

At this stage major concessions to the US are more of a threat than a possibility – but the farming lobby is right to flag up concerns and secure public support to kill off a bad idea before it can even make it to the drawing board.