Deputy prime minister Nick Clegg has signalled he will block any attempt to parachute a "Tory ideologue" into the job as head of the independent schools watchdog, Ofsted, after the removal of Labour's Sally Morgan.
In a direct challenge to controversial education secretary, Michael Gove, Clegg let it be known Lib Dem schools minister David Laws would preside over the appointment and would veto the man believed to be Gove's choice, Tory donor Theodore Agnew.
A blunt statement from a Lib Dem spokesman highlighted Clegg's anger, stating: "Education policy is far more important than rewarding a few Tory cronies. The Lib Dems will not let our children's education be dictated by some Tory donor ideologue."
Gove later appeared to contradict Clegg, saying the appointment would initially be recommended by an independent body but it was then up to him to accept or veto the suggestion.
There was a growing belief in Westminster that the furious response to the sacking of Morgan was a calculated pre-emptive manouvre aimed at blocking Agnew rather than a more general opposition to politicising the job.
The strength of the Liberal Democrats' anger at the way they were blindsided over Gove's decision not only appeared to have killed off any hope Agnew could now get the job but also represented one of the most serious splits yet in the coalition.
The affair escalated on the day Gove outlined the latest phase of his radical and hugely contentious agenda to shakeup the country's education system, including lengthening the school day to 10 hours, introducing testing at age 13 and supporting a more disciplinarian approach in a bid to see the state system apeing private schooling.
The education secretary has faced mounting opposition from the teaching profession over his reforms which have been branded as "back to the 1950s" and entirely out of synch with modern Britain.
He has previously been forced to re-write some of his proposals on the curriculum, but is as determined as ever to push through his agenda against all opposition, including what he calls the suffocating Whitehall "blob" of civil servants - interestingly in reference to a 1950s scifi film.
It is widely believed he wanted to give the job to his ally Agnew, currently a director in the department of education overseeing the Academies programme in England, in order to avoid future opposition from Ofsted.
But former Ofsted chief inspector, Sir David Bell joined the criticism of Gove saying he should not surround himself with "yes men".
Bell, who also worked alongside Gove as his most senior civil servant, wrote on an academic website: "The row over Ofsted's leadership shows the importance of retaining and being seen to retain independent voices near the top - not simply 'yes men'."
But, while the controversies over alleged politicising of Ofsted and Gove's reforms will continue, it appears he may be thwarted in his attempt to get a close advisor into the top job.
Any attempt to give the job to Agnew would meet stiff resistance across the board and it seems, to that extent at least, the Liberal Democrats have won this one.