Truancy was one of the problems dealt with by mentors

Ofsted, the education watchdog, found "learning mentors" had helped improve exam results, while cutting truancy and bad behaviour.

Mentors are part of the Excellence in Cities (EiC) scheme, under which inner-city schools and those in "pockets of deprivation" elsewhere are given extra money to reduce absentee and expulsion rates.

They also provide extra help for brighter pupils, often coming from the same backgrounds as the children in their care.

'Enthusiastic'

Ofsted made clear that, although EiC's overall impact was mixed, mentors had been a success.

They had had the greatest effect on exam results, as well as behaviour, of any of the EiC "strands".

Inspectors said: "Learning mentors have become an important part of school provision and are highly valued by teaching colleagues in primary and secondary schools alike, and by parents and pupils, especially those they support directly."

The best were "enthusiastic about working with young people", "sympathetic listeners" and "firm but fair".

It had been feared that pupils on the verge of expulsion might feel picked on for being singled out as needing help from a mentor.

But Ofsted found the opposite was more likely to be true, as children appreciated being treated like adults.

The report said: "Those who are benefiting most understand that the relationship with their mentor is a two-way process and that they must accept responsibility for their own work."

Learning centres

The best mentors gained parents' trust and in some cases were even able to encourage low-skilled mothers and fathers to go back to school themselves.

Chief inspector David Bell said the report uncovered "encouraging signs of progress".

School standards minister David Miliband described the findings as "extremely useful as we plan the future of Excellence in Cities".

He added: "Where Excellence in Cities schemes are running, the impact on standards has been measurable - results are improving at twice that of areas outside the programme."

However, Ofsted also published reports on a network of "city learning centres" set up under the main EiC scheme.

These are equipped with the latest computer technology and are for use by adults in the evenings.

These "functional, bright and spacious" facilities were proving useful to schools and the wider community, Ofsted reported.

But there was too little focus on improving children's achievement, even though they were doing work on computers of greater breadth and depth than was usual in their schools.

While there was some "effective and sometimes highly effective work" going on, progress on raising attainment was "uneven", said Ofsted.