School rebels in 'head teachers' spring'
There is something of a "head teachers' spring" going on at the moment.
It is the politest uprising, but it is giving ministers some very difficult homework over how schools in England are run and funded.
It is also unusual how heads are applying pressure - not through unions or strike threats, but by well coordinated and relentlessly reasonable demands.
These bastions of respectability are difficult opponents for the government to paint as the "usual suspects".
And the chancellor will be under pressure to find emergency money for schools in the Autumn Statement.
This week, almost every secondary state school head teacher in true-blue Surrey signed a ferocious letter to Prime Minister Theresa May expressing their "vehement" opposition to her grammar school plans.
Don't mess with the heads
In an unprecedented show of unity, heads said they were not going to put up with the unnecessary confusion and disruption being caused.
They also warned that the political acrobatics over increasing selection were missing the point over what schools really needed.
And if you talk to head teachers, you will hear a deafening chorus of what they are most worried about - a shortage of funding and teachers.
In another Tory heartland, West Sussex, head teachers have been mobilising.
Head teachers have marched on Downing Street, delivering a letter warning the prime minister that the lack of funds would mean cutting school hours or laying off teachers.
This was signed by every single state school head in the county.
Even more disconcerting for ministers, the head teachers wrote to 100,000 parents, warning that such cuts would be the consequence of inadequate funding.
This is a collision that the government will really want to avoid. Apart from not wanting such arguments in their own political backyard, head teachers are people with a lot of public credibility. Parents trust them, they are community leaders.
Ministers will have to decide whether they can risk calling their bluff.
It is a huge gamble for ministers, because the sight of pupils being sent home from cash-strapped schools would be a disaster.
But they will have to balance this with fears that if they agree to give extra funding to West Sussex schools, there will be a queue around the block from head teachers in other local authorities.
But there could be a way around this - such as a pot of emergency funding to allocate support depending on need.
Setting the rules
Head teachers have already pointed to the £500m that appeared to be available for the rapidly ditched plan to require all schools to become academies.
In the longer term, the much-postponed overhaul of school funding, the national funding formula, should relieve some funding gaps and local anomalies.
But there will be losers as well as winners in that change in funding.
And there will be other local groups of head teachers looking to flex their muscles and test the strength of their position.
Ministers can announce all kinds of initiatives, but they depend on head teachers and their staff to put them into practice.
Heads have been complaining for years about politicians overloading them with strategies and initiatives.
But in these strange political times, heads seem to be stirring into action and wanting to set their own rules.
If head teachers, reasonable, respectable and reassuring, decide they want things done differently, they will be a tough group to dismiss.