An £4 million programme to improve parenting skills has been branded a failure.

Research found the Triple P - Positive Parenting Programme - had minimal impact on families from deprived backgrounds in Glasgow and may even have increased social inequality because of the high drop-out rate.

Fewer than half of families completed the Australian derived programme and those with severe problems were the most likely to drop out, according to the report.

Dr Linda de Caestecker, NHS Greater Glasgow and Clyde's director of health, who approved the scheme, has rejected a £190,000 report - part funded by the Scottish Government - as a "flawed evaluation" that was based on limited evidence. The health board also helped fund the report.

About 5,000 children each year - 25,000 in total - were measured at the age of five from 2010 for emotional wellbeing.

The report found the social and emotional functioning of the children did not improve as the programme was introduced across Glasgow. The children of families who had dropped out were found to have the most problems.

Glasgow City Council, which also contributed towards the cost of the report, has accepted the findings but said more work was needed to evaluate the effectiveness of parenting programmes.

Children from Shettleston recorded the highest levels of emotional, social and behavioural problems, while those from Hillhead, Pollokshields and Linn had the lowest levels.

Families living in more deprived areas were more likely to start Triple P interventions, but those living in affluent areas were more likely to complete the course, the report suggests.

Research found mothers were given an initial confidence boost about their parenting skills from attending group sessions, which led to a perceived improvement in their children's behaviour, but this was only temporary.

The report, carried out by Glasgow University, has recommended NHS Greater Glasgow and Clyde does not continue to fund the programme.

Around 730 practitioners were trained to deliver the scheme between 2009 and 2013, with £3.8m spent in total.

More than 30,000 interventions were delivered to families, who attended sessions aimed at improving parenting skills.

Families who did complete the scheme reported high levels of satisfaction and reported improvements in parenting behaviours, emotional wellbeing and child behaviour.

The report found it was not possible to say whether these improvements were as a result of the intervention.

However, the health board said it rejected the conclusions of this report due to its lack of robustness.

Ms de Caestecker said: "The report was commissioned to evaluate the impact of the range of parenting support programmes that have been introduced across the city.

"However, there are a number of issues in the report that compromise the contribution it can make to our understanding of parenting support in Glasgow.

"Despite consistent and overwhelming evidence from parents and practitioners that Triple P is delivering improved outcomes, the report authors claim it is not possible to attribute these improvements to the parenting programme. The data in the report is limited, in part because parents did not complete the post-course assessment forms.

"No attempt was made by the authors to answer a key question of why people appear not to have completed these forms."

Professor Philip Wilson, study author, said: "The evaluation was independently and impartially conducted, and it has not given the answers the health board was hoping for.

"We have no agenda other than to conduct good quality research with a view to improving the design and commissioning of services for families, and in doing so the use of public money."

Matt McLaughlin, regional organiser for trade union Unison, said: "This independent report confirms what Unison members said all along. PPP is not fit for every family in Glasgow and Clyde because it is too middle class in its approach. It is not effective for the most disadvantaged or families who do not have English as their first language."

Matt Buttery, head of Triple P UK said: "We have worked closely with NHS Greater Glasgow and Clyde on the development and roll-out of the programme at a local level. We believe it has proved to be an effective tool to improve access to parenting support and increase participation in parenting programmes in the city."