Professor Sir Peter Scott, who has taken up the job of Commissioner for Fair Access, said there was danger in recruiting students solely on the basis of good grades.
He called on the four ancient universities north of the border to become ‘fully engaged’ in widening access.
The academic was appointed following the publication of a Scottish Government-backed report which said the current system was inherently unfair as it excluded bright pupils from poorer areas.
“University is not a reward for getting good grades,” Prof Scott told The Herald in an interview published today.
“The grades you get are evidence, but they are not entitlement and it is very dangerous to define that as an entitlement.
“There are competing ideas of what is fair and it may appear unfair in one context that people with better qualifications get squeezed out by people who come through after only having met the access threshold.
“On the other hand we have to accept that the current system is very unfair and there are certain people who are already excluded from higher education or who find it very different to get access.”
Mr Scott, a former education journalist who is now an academic at University College London, added it was down to Scotland’s universities to assess the merits of potential students.
“You need to recognise the diversity of universities, but ancient universities cannot say widening access is for someone else to develop so they don’t have to bother very much,” he continued.
“It is very important that ancient universities are fully engaged because they play a leadership role in the universities sector. Because of their fame, their prestige and their leadership role I think you have a right to expect more of them, while being sensitive to the changes.”