A headteacher says his school faces a "profound and imminent financial threat" if a new National Funding Formula spreading wealth is introduced.
Cardinal Vaughan Memorial principal Paul Stubbings says its implementation could reduce funding at the Holland Park school by 10%.
He is now urging parents to voice their opposition to the proposed new formula, which is currently under public consultation.
In his letter he says the formula, which would result in resdistribution of funds from London to other parts of the country, will “hit this school very hard”.
The new funding method is being proposed as Education Secretary Nicky Morgan described the current system as "unfair", as the amount of funding provided to school was uneven and left some with less despite them being similar to schools given more.
Urging people to respond to the consultation, Mr Stubbings, who says the school has already already experienced a cash freeze in funding since 2010 as a result of national austerity measures which will continue until 2019, said: “My hope is that once the government sees the volume of responses from parents and schools, they will consider levelling up funding to all schools, so that all schools benefit, rather than redistributing funds which will inevitably mean significant cuts across London.
“Let us be under no illusions: the financial threat posed to this school is profound and imminent. If we have the opportunity to let the government know this, then we should take it.”
Hammersmith and Fulham Council had also come out against the new National Funding Formula. In February it said the cuts it would cause “could threaten jobs, hit the range of subjects taught, and even damage the long-term viability of some schools”.
'Crisis in schools'
Cllr Sue Macmillan, head of education at the council said: “Figures provided by the group lobbying for changes to school funding show the large scale of the proposed cuts to spending, which would pile pressure on schools already struggling with teacher recruitment and ever-increasing overheads.
"This is why the council is determined to stand with teachers and parents and fight the plans.
“I have already written to all headteachers in our borough to share details of the government’s proposals, asking what a 10% cut to their funding from government would mean. They have indicated that cuts on this level could see teaching and support staff roles cut and many subjects discontinued.
"In the words of one headteacher, the likely cuts ‘would compound what is already a crisis in our schools’.
“There is also a danger that the hard-won increase in GCSE attainment in the borough, especially amongst our most disadvantaged pupils, would slide backwards, needlessly damaging the life chances of thousands of children,” she added.
A H&F Council spokesperson said would make a “full and forthright response to government” during the consultation, which ends on Sunday (April 17).
To have your say before the deadline click here or email the Secretary of State for Education at email@example.com