Four of Scottish farming’s former political heavyweights have outlined the reasons why they’re publicly supporting a Yes vote in the referendum on independence for Scotland on 18 September.

The quartet of former NFU Scotland presidents – John Cameron, John Ross, John Kinnaird and Jim Walker – joined the Scottish Government’s rural affairs minister Richard Lochhead at Yes Scotland headquarters in Glasgow to urge the country’s 65,000 farmers crofters and growers to follow their lead.

Questioned on why they’d waited so long to declare their support, Mr Ross said they’d taken advice from Mr Lochhead to wait until five weeks before the referendum. “We took the conscious decision that we’d allow the heat to come out of the arguments and wait until people’s minds were concentrated,” he said.

See more: Scottish independence: To stay or to go

The ex-leaders argued they had a combined wealth of experience of dealing with the UK government and Europe. Mr Walker also dismissed the experience of George Lyon, another former NFUS president and former MEP, who is leading the opposing Better Together campaign.

“He has no experience of dealing with Europe from a farmers’ representative point of view,” he said. “George Lyon has never been involved in CAP negotiations and he doesn’t bring a wealth of experience in terms of knowledge of what Scottish farming wants. He brings a political slant in every comment he makes about Scottish agriculture.”

All four men condemned Defra’s lack of commitment to Scottish farming and John Cameron cited the decision to distribute the whole of the Convergence Fund across the UK as unjustified and “against the legitimate expectations of Scottish farmers.” At the heart of their argument was the need for Scottish agriculture to be assured of a place in Europe.

John Ross, who was president of NFUS from 1990-96, said an independent Scotland was the only way for that to be secured.

“A No vote will mean years of uncertainty about a UK government’s EU membership and commitment and this will have very serious consequences for the future of Scottish farming,” he said.

John Kinnaird, NFUS president from 2003-07, argued that independence was the next logical process after devolution and said he was deeply concerned about a backlash against Scotland from Westminster if there was a No vote.

“On September 18 I’m not voting for a political party – I’m voting for independence,” he said.

Mr Lochhead described the former leaders support as a “huge boost” to the Yes campaign.

The announcement is in contrast to a survey of farmers in Scotland carried out earlier this year which suggested almost three quarters want to stay within the UK.

The National Farm Research Unit carried out a phone survey across April, May and June interviewing a representative sample of farmers in England, Scotland, Northern Ireland and Wales.

Of the 2,497 farmers polled, 529 were from Scotland and 72% of these said “no” when asked “Should Scotland leave the United Kingdom?”

Read more news stories like this