According to the SNP the routine hustings in Dingwall tonight blows a hole in the Prime Minister's case for refusing to debate with Alex Salmond.
The National Farmers' Union event will see Scotland's rural affairs and environment secretary, Richard Lochhead take on the Westminster minister for farming and fisheries, George Eustice.
The SNP leader at Westminster, Angus Robertson said: "The fact that a UK government minister is representing the No campaign in a referendum debate removes the last vestige of David Cameron's feeble argument against taking part in a TV debate against the First Minister. The only reason David Cameron is dodging debate is because he's feart."
A Better Together spokesman said: "Sadly, this is the kind of pathetic response that we have come to expect from the SNP."