Written by Professor Wyn Grant of the University of Warwick and the Farmer-Scientist Network, the report covers topics as diverse as the impact on the single farm payment, regulation, plant protection, world trade, animal health and welfare and migrant labour. The report is the result of a working party set up by the Network.

It was commissioned by the Yorkshire Agricultural Society, which hosts the Network, and it aims to inform and promote debate to highlight the issues which could potentially shape British agriculture.

It is particularly timely given the recent statement by Environment Secretary, Liz Truss at the Oxford Farming Conference that there is no "Plan B" should the decision be to exit Europe.

Speaking in advance of the report's publication on Thursday 4 February, Professor Grant said it was hard to see any advantage to British farmers in leaving the EU. In the event of a "yes" vote, the lack of contingency planning by the Government would inevitably lead to a period of great uncertainty, for at least two years, as the new regime took shape, making medium and long term planning for farmers extremely difficult, he said.

Most farmers' concerns centre on the effect any decision would have on EU farm subsidies. Against a backdrop of falling farm incomes, subsidies can make the difference of running at a profit or a loss. Without the payments the future of many farm businesses would be in jeopardy, warned Professor Grant.

"There is a perception in the industry that leaving the EU would reduce the burden of regulation. I do not think there will be a bonfire of regulations as the problem is not just from Brussels but from gold-plating by London. There are legal complexities which have not been considered."

Powerful and influential lobby groups in Britain would have a louder voice in a smaller arena, and British farmers would not have the advantage of their European counterparts, particularly the French, fighting the farming corner, and Britain would still have to abide by EU regulations if it wanted to continue to export to Europe. The likely introduction of import tariffs on British goods and border controls would all have an impact, making British goods more expensive.

North Yorkshire uplands farmer Richard Findlay pointed out that 40 per cent of UK lamb is sold to Europe so an exit would have a huge impact on that important market. "In most countries where there is no direct agricultural support, food is more expensive. It's a misconception that is a farming subsidy, it's not, it subsidises the cost of food on the shelves. Everyone has to eat and prices will go up. Food security should be higher on everyone's agenda."

Nigel Pulling, Chief Executive of the Yorkshire Agricultural Society, likened leaving Europe to a "leap in the dark."

"While there is some dissatisfaction with Europe there is at least certainty. What this report has highlighted is the complexity of the number of different issues we are facing, but the Government hasn't filled in any of the blanks.

"A real concern is that in any negotiations, agriculture would suffer against other sectors such as financial services and the pharmaceutical industry which make a greater contribution to the UK's GDP, but what could be more important than the food we eat."