Around one in six secondary school pupils are unable to write a simple story or message at the end of their second year, according to an education ministry inspectors’ report.

The problem is particularly acute with children in the lower streams of vocational training, but 4% of pupils in a pre-university or college course are also unable to write coherently, the report said.

“To be concrete, tens of thousands of school children risk being illiterate,” the inspectors said. “Basic skills remain a concern because the performance of pupils is not improving and may be worsening in secondary school.”

“We are concerned but we are not surprised,” inspector Matthijs van den Berg told broadcaster NOS. “We saw the same thing with reading and arithmetic.”

The inspectorate is now advising schools to invest in improving writing skills to raise overall standards. By integrating writing with other subjects, children learn to write better and, as a result, learn better overall, the inspectors say.