University students who are caught submitting plagiarised work are very rarely expelled, shows a survey.

A study found only 143 students caught cheating were expelled out of 9,200 cases - despite almost all universities threatening expulsion as a sanction.

Researchers warned of "inconsistent" penalties, the most common sanction imposed being to re-submit work.

The study of 86 UK universities also found a much higher rate of plagiarism among postgraduate students.

The report, from the Higher Education Academy and Joint Information Systems Committee, shows that despite the repeated warnings to students not to cheat by using someone else's work, those caught are unlikely to face particularly severe penalties.

More than 98% of students caught cheating were allowed to stay at their university - even though some of these students had been caught before.

Caught twice

Almost eight out of a hundred students caught plagiarising had already been caught on previous occasions.

"Concerns that the application of penalties for student plagiarism is inconsistent across the higher education sector would appear to be upheld by the findings of this research," says the report.

There have been widespread concerns about students copying work from the internet or buying essays from online essay writing services.

This study, which does not name any of the institutions which have provided data, found that the threat that cheating students would not be awarded a degree was rarely applied.

Instead, the most common penalty was to have to re-submit work, with a cap on the mark that could be achieved. The second most common sanction was a reprimand.

Other consequences for those caught plagiarising were an "informal" warning, a lowered mark or having to re-submit work without any capping on the mark.

Three times as many students were given an "informal warning" after being caught than were expelled.

This study also found that plagiarism was more frequent in postgraduate courses.

"It was surprising to observe that the recorded level of plagiarism among postgraduate students was so much higher than the recorded level among undergraduate student," says the report.

Across the universities as a whole, the cheating rate was about seven cases for every thousand students.