Grade inflation in universities and colleges may be fuelled by students threatening legal action when they do not get high marks, according to the head of the Irish qualifications agency.

Dr Jim Murray, the chief executive of the National Qualifications Authority –which is responsible for overseeing third level standards in Ireland – said there were "politically sensitive" reasons for the major rise in high-performing students.

In an email sent to a senior civil servant in the Department of Education last February, he said universities may also be driven to give higher marks because of league tables and their wish to perform well in them.

In the correspondence, released under the Freedom of Information Act, Murray said the "key question" that needed to be addressed ahead of commencing a study into grade inflation at third level was "how willing are all relevant stakeholders to investigate the underpinning causes, as some might touch on politically sensitive matters."

But he also warned that any inquiry would have to look at the "extent to which education, and the associated qualifications, are now seen by some learners as rights/entitlements and as commodities".

"There are some signs (necessarily anecdotal at this point) that some learners see the attainment of certain grades as a right and demand that they be given them, sometimes with the threat of litigation," he said. "Again, is this emerging culture fuelling grade inflation?"

Such was the level of concern about his views within the department that the official in question recommended in a separate email to colleagues that this be brought to former education minister Batt O'Keeffe's attention during a high-level meeting with his management team, the documents show.

Murray's concerns about students threatening legal action has prompted campaigners to suggest that universities and colleges may effectively "crumble" at the mere threat of legal action by students in relation to their grades.

"The problem comes down to the inconsistencies in the system when it comes to marking and assessment," Simon Quinn of the Network for Irish Educational Standards campaign group told the Sunday Tribune. "Some students know that if they put the frighteners on universities, they will not contest this."

Elsewhere in the email, Murray argued it is necessary to examine the extent to which the desire to develop fourth level education in Ireland has a "knock-on effect" on grades and qualifications. This is because more PhDs require more masters degrees and more 2:1s or first class degrees, prompting him to ask, "Is this a pressure to inflate?"