Farming Minister George Eustice has announced he will back the campaign to leave the European Union, meaning he will be campaigning on the opposite side to his boss, Liz Truss.
After David Cameron confirmed a June 23 referendum on Saturday, Mrs Truss, Defra’s Secretary of State, confirmed she would be backing the Prime Minister’s campaign to remain in the EU.
Mrs Truss, who has previously indicated eurosceptic leanings, said: "I am backing remain as I believe it is in Britain’s economic interest and means we can focus on vital economic and social reform at home."
But Mr Eustice, who campaigned to leave the EU before becoming an MP, has joined a number of prominent Conservatives, including Cabinet members Michael Gove and Iain Duncan-Smith and London Mayor Boris Johnson, as well as former Defra Secretary Owen Paterson, in backing the leave campaign.
Mr Eustice, who once stood as a UKIP candidate in EU elections and helped co-ordinate the campaign to keep the UK out of the single currency, said Mr Cameron’s re-negotiation had not gone far enough.
He said: "The Prime Minister deserves huge credit for delivering this referendum and we now have an opportunity to debate our future, how we are governed and how our laws are made.
"I have been an advocate of renegotiation for fifteen years but, in the end, despite the endeavours of David Cameron, the sort of fundamental reform I wanted to see was not possible".
"I have therefore come to the conclusion that the only way to deliver the change I want to see is to vote leave, end the supremacy of EU law and replace our membership of the EU with a new UK-EU partnership instead.
"I believe that if this country has the courage to act decisively and take control, then in five years’ time the only question people will ask is why we didn’t do it sooner."
Mr Eustice’s stance on the referendum, which has taken most people in the industry by surprise, Europe could be hugely significant as far as the Brexit debate is concerned.
Speaking recently at the Norfolk Farming Conference, Mr Eustice said the onus is on those campaigning to leave Europe, not the Government, to present a Plan B for what Brexit would look like for farmers.
“It will be for each side of the campaign to explain the pros and cons of staying in and the pros and cons of coming out," he said.
Up to this point, Defra Ministers have been criticised for their refusal to discuss what Brexit could mean for key areas like far support, trading relationships, regulation and access to EU labour.
Farmers will now be looking to Mr Eustice to start providing some of these answers.
CLA President Ross Murray said: “We respect the Farming Minister’s decision to support the campaign for the UK to leave the EU.
"As the person who has been responsible for farming policy since 2013, he is uniquely placed to spell out a vision for how UK farmers can trade with EU and the rest of the world; and the future of rural economy outside the common agricultural policy.
“Ten days ago the Minister told a farming conference that the onus would be on the Brexit campaign to set out a vision for agriculture in the event the UK decides to leave the EU.
"Now he has declared his position the onus is on him to do so."
NFU President Meurig Raymond said British farmers must have more information about how their businesses will be affected if Britain stays in, or leaves, the EU.
In light of the ongoing uncertainties the NFU is currently working with leading agricultural research institute from the Netherlands, LEI Wageningen, to model the potential impact of a Brexit under three separate trading scenarios. In each of the scenarios the effects of three different levels of agricultural support will be estimated.
The impact of these policy changes on UK commodities production, domestic farm-gate prices, farm incomes and trade flows will be modelled.
Mr Raymond said: "British farmers must not go into an EU referendum without all the information. If Britain stays in the EU we need to know what steps will be taken to make European agriculture more competitive.
"And will there be an EU commitment to regulations that are more science-based and proportionate? If we remain a member state, will we be able to remove some of the blocks to progress – such as barriers to biotechnology?
“If we leave the EU what will a British agriculture policy look like and what is the future of support payments? How will British farmers access the European market and will the UK be more open to imports from outside Europe?
The implications of the EU referendum for farming will be debated at this week's NFU’s Annual Conference, with former Liberal Democrat MEP George Lyon speaking for the Britain Stronger In Europe group and Daniel Hannan MEP making the case for a Brexit.
CLA president Ross Murray said the association would 'not be telling our members how to vote' but would be playing a full part in the debate up to June 23.
He said: "It is vital that our members and the wider rural business community have the best information possible to help them decide how to vote.
“There are fundamental questions about how we ensure there are growing markets for our agricultural and other products and services; how we ensure there is a support system in place that manages market volatility and invests in our environment; and how we ensure we have the labour we need.
"These must be addressed head on and not skirted over by either campaign."