Universities and colleges need to improve the standard of English on campus to avoid compromising educational standards, a report for the education ministry has warned.

The research watchdog KNAW raised concerns that too many institutions lacked a coherent policy on the issue of using English as the language of instruction. It urged them to pay more attention to the language skills of both teachers and students.

Around 20% of undergraduate-level courses were taught completely in English in the last academic year, a figure which rises to 60% for master’s courses. For vocational colleges the proportion is 8%.

The use of English is potentially a barrier to students from migrant backgrounds or with lower-level secondary education, but colleges need to balance this with the needs of an increasingly international student population, the report said. English did not necessarily affect the standard of teaching provided proper language and intercultural support policies were in place.

The decision on whether to teach classes in English should be taken carefully and on a subject by subject basis, rather than automatically, the KNAW said. In subjects where English textbooks are used it made sense to use the language in the classroom, while for others, such as Dutch law, Dutch was a more logical choice.