Details of a private meeting between education secretary Justine Greening and members of the Grammar School Heads' Association have been published on the latter's website.
The meeting - called ‘Lifting the ban on grammar schools’ - was also attended by schools minister and Bognor/Littlehampton MP Nick Gibb.
For months, headteachers in West Sussex have pleaded with the government for more money as they attempted to make their already massively over-stretched budgets stretch even further.
Their appeals for emergency funding fell on deaf ears, as did calls for state-funded schools to be able to access the £384m previously set aside for the government's academisation programme.
In addition, 'stealth taxes' that will not be covered by the new National Funding Formula will see their schools financially worse of than before.
The message from the government had been a clear 'we don't have the cash'.
A statement issued today by members of the Worth Less? campaign for fairer funding said: "Throughout our campaign school leaders have sought to be ‘relentlessly reasonable’; now we are simply furious."
They added: "We are literally scrabbling around for any form of cash like a desperate person checking down the side of their sofa for the odd pound coin or two."
The heads met with Mr Gibb and West Sussex MPs last week to discuss the funding crisis faced by the county.
They came away from the meeting feeling they had at least been listened to and confident some small amount of progress had been made.
That confidence has been replaced with incredulity and the headteachers have written to MPs seeking answers.
The campaigners said: "We would respectfully request...that political leaders explain and account for policies and spending decisions that disadvantage not just those schools and children that are ‘just managing’ but those schools that simply aren’t being allowed to do even that."
A spokesman for the Department for Education told the BBC ministers would "respond in the Spring" with their formal grammar school proposals, which would "make more good school places available, to more parents, in more parts of the country".
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