Berwickshire MP Michael Moore has expressed concerns that rural areas on both sides of the border will suffer from Scottish independence.
The Secretary of State for Scotland warned that farmers and traders would suffer if Alex Salmond succeeds in breaking away from the Union at next year’s referendum.
MPs say they do not know what independence would mean for Single Farm Payments and other support and what impact this might have, not just on Scotland but on English trading partners.
Mr Moore, responding to a question by Hexham MP Guy Opperman, said: “As one of my honourable friend’s neighbouring MPs, I recognise the importance of Hexham and north Northumberland.
“As he knows, in a farming context and in so many other ways, any kind of legal border between Scotland and England would be an absolute disaster.”
Mr Opperman said a new country would need to apply to join the EU and put border controls in place.
“From farming to tourism, to simply doing business, the negative effects of a new legal border between England and Scotland would be a real problem for our local economy You will effectively end up with a legal border crossing at Berwick, with who knows what kind of checks in place.”