Four former leaders of the National Farmers' Union Scotland have backed independence, arguing a Yes vote would secure the future of the industry.

John Ross, Jim Walker, John Kinnaird and John Cameron say remaining in the UK could put farming at risk given Prime Minister David Cameron's proposed in/out referendum on Europe.

They are urging 65,000 farmers, crofters and growers across Scotland to follow their lead in September's referendum.

Mr Walker, who was president of the union from 1998 to 2003 and farms near Sanquhar in Dumfries and Galloway, said: "If, as seems increasingly likely, the UK leaves the EU after a promised in/out referendum, the funding that currently comes from Brussels will be left with HM Treasury and Scotland will be much more dependent on its decisions.

"Worryingly, we know from the decisions the Treasury has consistently taken over the last 20 years, irrespective of the party in power, it will prioritise cutting expenditure on food, farming and rural development rather than encouraging investment.

"Independence, on the other hand, will allow us to really back our food and farming sector, set our own priorities and sit at the European negotiating table, no longer affected by the UK Treasury indifference."

Mr Ross, from Portpatrick, Dumfries and Galloway and union president between 1990 and 1996, said: "Farming and rural affairs need to be at the forefront of all future Scottish Government thinking - and being fully committed members of the European Union is an essential part of that policy.

"An independent Scotland is the only way that this can 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."

Mr Cameron, who farms at Balbuthie in Fife, became the union's first long-term president in 1978.

He said: "My experience is that the development of agriculture policy has been handled with much better understanding between the industry and the Scottish Government and that this position will only be strengthened with independence."

Mr Kinnaird, who farms in East Lothian and was union president from 2003 to 2007, added that a Yes vote is the "logical" next step after devolution.

Rural Affairs Secretary Richard Lochhead welcomed their support and said it sent a "powerful message" throughout Scotland.

He said: "These four former NFU presidents are big hitters with a wealth of experience in dealing with UK governments and ministers including prime ministers in recent decades.

"They care deeply about the future of their industry and the fact they have reached the conclusion that our key agriculture and food sectors will be better safeguarded and promoted with independence is a momentous moment in the referendum campaign."