They found that a course run by the Institute of Communications Studies had not properly consulted external examiners who act as the guardians of university standards.
Leeds is only the second "old" university to have a course effectively failed by inspectors from the Quality Assurance Agency, the body set up to monitor standards in higher education. The report, which was published yesterday, found important shortcomings in the university's Bachelor of Broadcasting degree, which is taught and run in conjunction with the BBC.
It said there was "clear evidence of a serious breach of the university's examination regulations."
The report continued: "The assessors have no confidence that the operation of the external examiners' system in the Institute of Communications Studies provides the necessary level of assurance of the quality of provision.
"There is clear evidence that the university's own quality assurance systems have been ineffective.
"They did not identify these breaches of regulations ... The assessors consider that the operation of the university's examinations procedure was seriously deficient in allowing degree classifications to be decided by an internal meeting at which no external examiner was present."
The degrees, awarded last year, will stand.
The university defended the course, pointing to a string of top grades for teaching on the course, and insisted the problem was a one-off.
A statement said an "administrative oversight" led to degrees being awarded without the external examiner signing off the grades. It said all the courses making up the broadcasting degree had been subject to external checks, and no changes were made to grades at the final examiners' meeting. Action had been taken to prevent a repeat of the problem.
Inspectors said teaching on the courses was of high quality and praised students' work. The inspectors will return to Leeds within a year to check that improvements have been made.
External examiners are the cornerstone of university degree standards. They are experts in their field, who visit other universities to monitor grades for undergraduate and postgraduate students.Reuse content