Schools are bracing themselves for more details on plans to redistribute education funding through a new national formula but heads are warning that all areas will remain financially worse-off, whatever the outcome.

The government’s response to a consultation on the proposed schools national funding formula (NFF) is due to be published “mid-week”, the Department for Education has confirmed. Union leaders are expecting an announcement on Wednesday. 

The formula will be used to decide how education spending is allocated based on factors such as levels of deprivation, pupil prior attainment, the number of pupils for whom English is an additional language and salary costs.

It is being brought in to tackle wide variations in per-pupil funding rates across the country, from £7,007 per pupil in Tower Hamlets to £4,151 per pupil in Wokingham in 2015-16. Under the current system, the needs of different areas are based on assessments made a decade ago.

The new formula is set to come into effect in 2018-19, after education secretary Justine Greening announced in July that its original 2017-18 implementation date would be delayed by a year.

Although there will be winners and losers under the plans, heads say that all schools are facing real-terms cuts, as budgets continue to be squeezed.

Schools are facing above inflation rises in staff costs and have also been hit by a decision to cut the Education Services Grant, used for school improvement and other costs including redundancy payments, by £600m over two years.

Association of School and College Leaders interim general secretary Malcolm Trobe said: “All schools are facing effective reductions, so even those that might gain from NFF will probably still see real-term reductions in their ability to purchase what they need.”

Mr Trobe also stressed that it was important that the £500m in transitional funding pledged by the government was available in 2017, rather than waiting until 2018.

He added: “The bottom line has to be that, given all the pressures, they need to put some more money into the school system.”

Valentine Mulholland, National Association of Head Teachers director of policy, said that, while the government had published the different factors that would feed into the formula, the key detail to emerge this week would be how those factors are weighted.

She said: “Schools in areas that have seen a lot of immigration, or where deprivation levels have grown, are going to see quite significant change.”

However, she said that predictions that London and urban areas would lose out were “too simplistic”, as their higher salary costs would be taken into account.

The document due this week will set out the government’s response to a consultation on the basic principles behind a funding formula and wider changes to the school funding system.

Unions are expecting a set of more detailed proposals from ministers followed by a second 12 week consultation.

In a letter sent today to schools standards minister Nick Gibb, Commons education committee chair Neil Carmichael said the “unfortunate” delay to the national formula scheme had “exacerbated existing funding pressures across England”.

It said: “Many schools find themselves unable to deliver essential functions, and the way in which funding is distributed between schools is a second-order question.”

The letter symbolised the committee’s growing interest in the financial position of schools, he added.

It was in response to a letter from Mr Gibb sent on 23 November, which had suggested postponing a December evidence session until January, to allow members to fully consider the material due to be published before the Christmas recesss.

Mr Gibb confirmed then that the next publication would reveal “detailed proposals for the formula and factor weightings”. It added: “It will also set out the impact our proposals would have on all school and local authority budgets”.

Want to keep up with the latest education news and opinion? Follow TES on Twitter and like TES on Facebook