PRIVATE tutoring has ballooned into a e1.5 billion (pound;1bn) a year industry, according to new research. Since many university students and teachers do not declare their earnings from tutoring it could even be as high as e2.3bn a year, with one in three pupils receiving out-of-school tutoring, according to the Munich-based Institute for Youth Research.

However, unlike other countries where private tutoring is increasing, the growth in demand is not due to competitive examinations but to a lack of support for struggling pupils, as teachers “teach to the middle” and aim lessons at average students.

Parents say that they can no longer rely on teachers to identify and deal with their children’s specific problems despite falling class sizes. Average classes are 27 in Berlin and 25 in most other states.

The extent of tutoring in Germany could be higher still because tutoring by parents, older siblings and other family members is not included in the research. A decade ago, about one in five received supplementary tutoring.

One of the largest commercial tutoring organisations, Studienkreis (Study Circle) says business is booming. In the mid-1990s it had 400 outlets nationwide compared with 1,000 now. The number of its clients has risen from 500,000 a year ago to 600,000.

“Parents in employment do not have time to help their children,” said spokeswoman Alexandra Schlueter. “And many were at school a long time ago and do not know the material.”

The main problem is maths, particularly around age 13-14 when algebra kicks in. “Almost half of all tutoring is in maths. And 80 per cent is in the core subjects: maths, German and English,” said Ms Schlueter.

The number of primary school pupils needing tutoring has also gone up. Primary teachers are not trained to provide individual attention and parents say that if a child is lagging they have no choice but to pay for tutoring, particularly if they want a grammar-school place.

Parents increasingly favour grammar school over the more vocationally orientated and once highly regarded Realschule which takes the middle-ability range.

Because of parental demand, grammar schools have widened their intake from the top 15 per cent of the ability range in the 1970s and 1980s to the top 20-25 per cent now, although the schools insist that standards have not fallen. This has led to a demand for tuition for the least able pupils in grammars.

Research shows that most who receive tutoring are at selective grammars. “Many struggle to keep up, but parents do not want their children to transfer to the Realschule, so they pay for tutoring,” said Ingrid Stahl, who teaches English at a Berlin grammar.

Up to 15 per cent of any one class at her school did not receive a grammar school recommendation from their primary school, she said, and most have “substantial out-of-school tutoring”.

Research shows that tutoring not only improves pupils’ marks in school tests but also has a motivational effect, reducing fear of exams and increasing confidence and self-esteem.