Sheep farmers' concerns of no-deal Brexit
Creating a market for UK lamb to match what is exported to the EU could take up to 10 years in the event of a no-deal Brexit, sheep farmers have warned.
A third of lamb produced in the UK is sold in the EU.
Farmers and crofters fear rules on foods from non-EU and tariffs will cause a collapse of this market.
The UK government said there was "significant work" under way to ensure that UK exporters could maintain access to EU markets after Brexit.
The Scottish government said the UK leaving the EU without a deal would be "catastrophic".
Phil Stocker, of the National Sheep Association, said efforts were being made to grow the domestic market and there had been some successes in selling UK lamb to Japan and countries in the Middle East.
But he told BBC Radio's Good Morning Scotland programme there was not enough time to create a market big enough to handle the amount of lamb produced.
He said: "If you think of the volume that goes into the European market and think of the time if takes to agree trade deals, it is going to take some years - six, eight, 10 years - to open up equitable markets across the world."
Robert Macdonald, a hill sheep farmer in Badenoch and Strathspey and an NFU Scotland committee member, said producers were already facing challenging times as costs of raising lambs this season had "skyrocketed".
On his sheep farm, like others across Scotland, he is awaiting his pregnant ewes to give birth and has been spending money on the additional food needed for the sheep at this time.
On Brexit, he said: "In a normal season we would be selling the lambs on in August and September.
"They would go on to lower ground to 'finishing' farms. They would be fat in the spring next year and the vast majority would be exported into Europe.
"If we have a no-deal Brexit the consequences are potentially catastrophic."
He said his hope was that a disaster for the industry could be averted by government agreeing to a system of payments to help farmers through a no-deal situation.
Rural Economy Secretary Fergus Ewing said he had been warning the UK's environment and rural affairs secretary Michael Gove against a no-deal Brexit.
He said: "I am extremely concerned, and I have put these concerns to Michael Gove on numerous occasions, that a no-deal would be catastrophic for our hill farmers.
"It would mean the imposition of tariffs at 40 to 45% and that would see the lose of markets in the EU, which is essential for Scotch lamb."
The UK government said it was preparing as "any responsible government would" for the possibility of no deal, and there was significant work under way to ensure that UK exporters could maintain access to EU markets.
It is considering all tariff options for a no-deal scenario that would work in the interests of farmers, consumers and businesses.