Under-fire Cabinet minister Andrew Lansley has turned up the heat on education secretary Michael Gove by claiming the flagship pupil premium policy has failed to resolve "fundamentally unfair" funding inequalities.
The health secretary, whose NHS reforms have come in for widespread criticism, has signed a letter to his fellow Tory Cabinet minister, which argues that the current school funding system disadvantages vulnerable children, and leaves schools in some parts of the country worse off than others.
While welcoming extra funding for young people from deprived backgrounds through the pupil premium, the letter, signed by Mr Lansley and five other Cambridgeshire MPs, claims that annual funding for the county's schools - currently at #163;4,643 per pupil, putting Cambridgeshire 143rd out of 151 English local authorities - is "insufficient" to meet even their "basic education needs".
And Ivan Ould, lead councillor for children and young people's services at Leicestershire County Council - the English education authority with lowest per-pupil finding - said that the funding gap between authorities had widened since the pupil premium was introduced.
Annual per-pupil funding in Cambridgeshire is #163;441 less than the national average - and #163;525 less than in neighbouring Peterborough.
"We believe that this situation is fundamentally unfair and fails to reflect the needs of young people in Cambridgeshire accurately," the letter says.
"We are also concerned at the impact this poor level of funding is having upon teaching and learning... Cambridgeshire schools find it difficult to recruit senior and middle teachers due to their inability to offer competitive financial incentives, despite the high housing and transport costs of living."
The MPs called for a minimum national funding entitlement to be introduced for students.
"The crucial issue is that a reasonable amount of funding is identified as a 'basic funding entitlement per pupil' in any funding formula, whether it funds schools directly or is distributed via the local authority.
"We are therefore asking that every pupil receive a basic funding entitlement that reflects the cost of educating a child anywhere in the country," the letter adds.
Councillor Ould, chair of the f40 group, which represents the 40 lowest-funded local authorities in England, said he was "totally in support" of the MPs' stance.
He said his own authority received #163;850 per pupil less than neighbouring Leicester City Council, making it the lowest-funded council in the country.
"It is grotesquely unfair that a child can be getting #163;850 less than one on the other side of the street," he added.
Mr Ould said that the funding gap between Leicester and Leicestershire stood at just #163;310 in 1997, and said that the pupil premium had "certainly made a difference" to the wider gap which has emerged.
A Department for Education spokesman said: "We agree that current school funding system is unfair and illogical, with huge variations in levels of per pupil funding.
"We've been clear that we plan to reform the system - that's why we recently consulted how school funding can be made fairer, and we will set out the next steps in due course."