The national strategy for teaching 11 to 14-year-olds has improved teachers’ skills but failed to raise pupils’ results, according to inspectors.

The Office for Standards in Education this week reported that there was no evidence of “widespread, significant improvement” in test results for 14-year-olds at the first schools to try the Government’s key stage 3 strategy.

An analysis by Ofsted of results in 2001-02 showed that the 205 pilot schools made fractionally less improvement in English than other secondaries.

A fifth of England’s 3,500-odd secondary schools had not done enough to raise achievement in maths since the strategy was introduced nationally in 2001. Weak departmental heads and staff shortages were often to blame.

Pupils had particular difficulty in applying maths. The use of maths was poor in half the schools and rarely good even in the better ones.

A third of the schools surveyed had been hampered by problems recruiting well-qualified teachers.

Chief inspector David Bell said that the strategy had been introduced gradually, starting with pupils who began at the secondary schools three years ago, so its real impact would not be clear until after tests this May.

The report stated that the pound;489 million strategy had produced “promising signs” and that schools had welcomed it.

It added: “The strategy has had a positive impact on teaching, notably in relation to the setting out of lesson objectives, greater variety and purposefulness in activities, and more involvement of pupils in their learning.”

However, many teachers missed out on initial strategy training, especially for science. Ofsted urged schools to make sure all teachers were informed of the strategy.

The National Union of Teachers said the report echoed the findings of a survey it conducted two years ago, which showed that 50 per cent of teachers in the pilot felt they had not received enough training.

John Bangs, NUT head of education, said: “The lesson the Government should take on board is that teachers must be involved in developing their training and have the time to benefit from it. Without that, the impact of the strategy will be patchy, as Ofsted has found.”

Mr Bell said: “Teachers have responded well to the KS3 strategy and their teaching has benefited.

“I am also pleased to see that most local education authorities have made an effective contribution to the implementation of the strategy for 11 to 14-year-olds.

“However, the report also identifies issues that need attention and I hope our recommendations will help to make sure that these are addressed.”

“The Key Stage 3 Strategy: evaluation of the second year” is at www.ofsted.gov. ukpublications