Prime Minister David Cameron has made an appeal to the livestock industry in a speech setting out the case for remaining part of the European Union.

The Prime Minister, who is backing the campaign to stay in the European Union ahead of the in-out referendum he has called for 23rd June, said an exit from the Union could cost beef and sheep farmers £330 million in lost export revenues. He said the figure is based on World Trade Organisation rules.

Speaking on a visit to Wales, Cameron said agriculture would “Suffer enormously” if Britain let the EU, and used livestock exports as an example; he claimed that, as a result of extra trade tariffs, the cost of exporting beef would increase by £240m, whilst lamb exports would cost farmers an extra £90m.

Currently, 90% of UK beef and lamb exports of to other EU member states; worth approximately £605m. In all, more than 60% of Britain’s agricultural exports go to other EU countries. Experts like Trinity College Dublin’s Professor of European Agricultural Policy Alan Matthews have warned that Europe is more valuable to the UK in terms of trade than vice-versa.

Though exit campaigners have suggested the UK could forge deals with the U.S, New Zealand, India and a range of other states around the world, experts have pointed out that, even if subsidy levels remained unchanged in an independent Britain, farmers would have to compete with cheaper imports as a result of these deals and would very likely be worse off.

Cameron said the European single market “Gives [farmers] access to 500 million consumers, to whom they can sell their goods on an open, unrestricted basis. No tariffs, no barriers, no bogus health and safety rules designed to keep our products out.”

Farming is worth almost £10bn to the British economy as a whole, the Prime Minister said.

The results of Yougov polls conducted in February and March and released earlier this week suggest a slight majority in Britain want to remain in the EU, though the margin remains incredibly tight.