The claims come from Nicola Sturgeon's Standing Council on Europe came as the First Minister announced plans for a second Scottish independence referendum yesterday as the SNP said it “will never consent to this extreme Tory Brexit”.
The letter says: "The UK government's approach risks condemning the country to years of further negotiations with the EU, in a poisoned atmosphere, whilst we suffer the consequences of having crashed out."
A legal challenge will be heard in the Court of Session in Edinburgh today to try and ensure Boris Johnson requests an extension to the Article 50 process if he refuses to abide by the terms of the Benn Act.
The act, which was introduced by Labour MP Hilary Benn, was passed by the UK Parliament last month following claims the PM would ignore the wishes of elected politicians and deliver a no-deal Brexit.
The Prime Minister has repeatedly said that no matter what the circumstances the UK will leave the EU on October 31.