Pressure is mounting on the government to provide “full detail” of promised support for sheep farmers in the event of no-deal.
The call is being made on minister in charge of no-deal planning Michael Gove.
It follows fresh concerns in this week’s Shetland Times about the “catastrophic” impact steep tariffs risk having on lamb exports.
Concerns have risen that lamb could face EU tariffs of up to 40 or even 50 per cent.
A no deal Brexit is now potentially less than one month away, although ministers insist a trade agreement with the EU is still possible.
The latest intervention – from MP Alistair Carmichael – follows a meeting held between isles food producers and Mr Gove, as well as the Defra secretary George Eustice.
At that point producers were told mechanisms were in place to support farmers and crofters in the event of no deal.
Now, in a letter to Mr Gove, Mr Carmichael has asked what discussions were taking place between the UK and Scottish governments to make measures to support sheep farmers a reality.
Wider concerns surround agriculture funding, with Mr Eustice facing questions on how the £595 million budget for the Scottish government would be determined in future.
Mr Carmichael said: “Assurances from government ministers are welcome but they mean little until we can get a better picture of what the support for food producers will look like after December 31st.
“Farmers and crofters have a right to know the specifics of these support mechanisms because it is their livelihoods that will be first on the line in the event of severe disruption.”
He added: “If there are mechanisms ready and in place then we should know the specifics. If they are not there then we should know why, particularly with less than 30 days to go.
“We know that funding is there for now, but we have yet to learn how long it will last, or how it will be used.
“As we enter the final weeks of EU negotiations, farmers and crofters face potentially catastrophic market changes that will put their viability at risk. They deserve better than vague reassurances from the government.”
Speaking on Radio 4 this week, Mr Eustice said a deal was still possible, arguing that at some point, as he saw it, there would be “an outbreak of common sense”.
“EU membership comes at the cost of bad governance,” he told the BBC’s Nick Robinson.
“The real prize of leaving the EU is to regain that ability to govern effectively.”