Sir Peter Housden was giving evidence to Westminster’s Scottish Affairs Committee on the relationship between the two governments.
He was Permanent Secretary to the Scottish Government between 2010 to 2015.
Committee member John Lamont asked him: “Thinking back to 2014 and the referendum, is it fair to say that relations between the two governments were quite tense?”
Sir Peter replied: “Well, interestingly, yes and no. At senior level they could not have been more tense on occasions but nevertheless there were important channels of communication that were being held open.
“I saw it as my responsibility, with officials in the UK Government, to keep those channels open.
“This is a lot about how senior people conduct themselves in these sort of spaces and remember their broader commitment to civil service principles.
“I felt that was very well adhered to on both sides of the equation.”
He added: “There were occasions when I would absent myself from conversations around the Permanent Secretaries’ table in order not to embarrass and to allow a full discussion of the UK Government interests, and all of that worked in a way that many people outside Government and Parliament couldn’t understand, but it did.
“For me it worked well and contributed to the outcome, we were able to keep those relationships going.”