The NFU council has voted overwhelmingly to back to the campaign to remain inside the EU.
While the union will not be actively campaigning, it has adopted a firm stance ahead of the EU referendum, following a four-hour debate by the NFU council.
The council agreed the following resolution: “The NFU Council resolves that on the balance of existing evidence available to us at present, the interests of farmers are best served by our continuing membership of the European Union.”
Speaking at the NFU’s headquarters immediately after the vote, NFU president Meurig Raymond said the union was legally required to come up with a clear position on the Brexit debate in order to provide further information to members.
He said: "We have collated a lot of evidence and information and held 28 meetings across the country in the past fortnight.
"To be allowed to provide further information it is important we sign up to the Electoral Commission and the overwhelming view today was we must sign up to the remain camp in order to provide that further information."
"If we had decided to stay neutral we would have been limited to a spend of £10,000. As a professional organisation representing 70 per cent of the farming industry we would have been hamstrung."
Mr Raymond acknowledged some NFU members ’have already made their mind up to vote against staying in Europe’ but said: "We respect their views but today the delegates were representing the delegates in their counties."
"It was an excellent debate, probably one of the best debates I have heard in council in 20 years.
"It was very passionate and, at the end, there was an overwhelming view of council from across England and Wales that this ought to be the line the NFU takes."
Mr Raymond said a vote to leave the EU would put UK farmers at a ’competitive disadvantage’.
He said: "The big, big issue today was market access. Nobody knows what the conditions of trade would be to the EU market of 500 million people.
"We could easily end up with no import tariffs on food coming into the UK but with the EU imposing tariffs on our food exports. So we would have the worst of all worlds - greater competition from imports and reduced access for exports."
He said the other two big issues were the availability of EU labour to the farming and processing sectors and the future of support for British farming ’at a time when British farmers are really struggling financially’.
Former NFU President, Peter Kendall, said: "Britain's membership of the EU is essential for the farming and food industry so it is hugely significant that the NFU has today confirmed that it believes UK agriculture will have a more secure future within the EU.
"Being part of the single market - our home market of 500 million consumers - is crucial to the long term prosperity of farming in this country.
"Leaving the EU would make trading farm products significantly harder, financial support uncertain and leave farmers facing years of uncertainty. That is too much of a gamble and one our industry cannot afford to take.
"That is why I fully welcome the decision from the NFU who have made it clear that Britain's farmers are stronger, safer and better off in the EU."
Leading Brexit campaigner Farming Minister George Eustice said: "Farmers are very divided over whether we should stay in the EU and the NFU are right to remain neutral and not to campaign.
"Their own recent study showed that, if we left the EU, there would be a firming in farm gate prices and a recovery in farm incomes.
"Virtually every problem that the NFU complain to me about is a direct consequence of dysfunctional EU law.
"Farmers who want to see change and a better future should vote to leave and take control so that Ministers have the power to sort things out."
In a statement the NFU said it ’recognises and respects the diversity of views among its membership’.
It said: "The NFU’s position is based solely on an evaluation of the agricultural merits of the case and the NFU is fully aware there are many wider issues at stake.
"The NFU will not be actively campaigning in the referendum; it will not be joining with any campaign groups and it will not, in any circumstances, advise its members how to vote."
"It is, however, the case that the Electoral Commission rules governing the referendum in effect mean that the NFU will be required to register to enable it to continue to carry out its essential role of informing members of the issues as they affect farmers."
The vote at NFU council looked at key issues including:
The council vote followed 28 roadshows held across England and Wales to enable NFU members to debate and discuss the key issues of the impact of leaving the EU on farming.
The meetings discussed a report commissioned by Dutch University Wageningen, which looked at the impact of direct payments and access to market under various scenarios in the event of the UK voting to leave the EU.