Less than half of the savings identified by the  Department for Education's controversial cost-cutting advisers are "able to be implemented", a new report reveals.

The finding is contained in an evaluation of the DfE's controversial pilot that sent financial experts known as School Resource Management Advisers (SRMAs) into academy trusts to find areas where budget savings could be made.

It also found that around a quarter of the trusts said the advisers did not come up with anything they hadn't already thought of and that some secondary trusts had to deal with advisers with no experience in their sector.

Savings: DfE stands by cutting school meal portions

School funding: One in four maintained secondaries in the red

Related: Depth of school funding crisis revealed

The evaluation reveals that schools are planning to implement just 48 per cent of the savings recommended by the advisers within three years – the period for which academy trusts must produce financial forecasts.

The DfE was last year forced to defend its pilot after the Commons Education Select Committee highlighted that SRMAs had suggested one school could save funds by cutting the size of pupils' dinner portions. Another recommendation was to reduce admin staff contracts to less than 52 weeks per year.

Today’s report highlights initiatives taken by trusts to save money as a result of SRMA visits such as a reduction in the amount spent on senior leadership teams.

The SRMAs were able to identify savings worth just over £35 million in the 72 academy trusts they worked with.

The DfE followed up with 61 of the trusts that were still open and were in a position to be evaluated.

Among these 61 trusts, 24 had made £4.9 million of savings since the SMRA visits were carried out in 2017-18, and 54 in total were planning to make a further combined £10.8 milion of savings over the next three years, bringing the total to £14.98 million.

This represents less than half (48 per cent) of the £31.24 million of savings identified by the SRMAS for the 54 trusts.

Today's evaluation report states that it is "clear" that SRMAs were able to recommend substantial opportunities for improved resource management "in most instances".

But it acknowledges that schools did not feel able to act on all these opportunities.

It states: "Where we followed up with trusts, almost half of the opportunities were able to be implemented, meaning overall trusts have reported that they are able to make combined savings of almost £15 million after working with an SRMA."

The report highlights several reasons why schools chosen not to implement all the SRMA recommendations.

It says: "In some cases, the conditions necessary for recommendations to be implemented have not materialised. For example, recommendations linked to joining a multi-academy trust (MAT) may not happen.

"In other cases where trust boards have decided not to take forward some of the recommendations around altering the staffing structure, reasons include significant changes to circumstances such as increasing pupil numbers or a school having a negative Ofsted inspection.

"In cases where trusts remain in a cumulative deficit position, [the Education and Skills Funding Agency] will test and challenge these decisions, but will always work with the trust and the regional schools commissioners to ensure educational improvement is protected and supported."

The evaluation also found that, in a “small number of cases”, there was a perception by the trust or the Education and Skills Funding Agency lead that particular SMRAs did not have a sufficient understanding of integrated curriculum and financial planning.

“This was most notable in one or two cases where SRMAs with exclusively primary school experience were deployed to secondary SATs,” it notes.

The majority of pilot trusts (94 per cent) responding to a DfE poll said they had rated their experience of working with an SRMA as "good" or "very good".

But nearly a quarter (23.6 per cent) disagreed or strongly disagreed that the SRMA had made recommendations they had not already previously considered.

Most of the savings related to the way staff were being deployed – which is "unsurprising given most school spend is on staffing", notes the report.

The news came as schools minister Lord Agnew today revealed that, after the pilot was extended, a further £137million of possible savings were identified across 357 schools.