MPs are expected to table a parliamentary motion when they return from their summer recess next week, demanding they have a veto over the new appointment as Commons Clerk.
Such is the intensity of the row brewing that Westminster insiders feel that a challenge to Mr Bercow, who has been Speaker since 2009, now looks inevitable.
Following a General Election, the incumbent Speaker usually, if he or she so wishes, remains in post even though there is a vote. But while Mr Bercow has let it be known privately he wants to remain in his prestigious role for at least 10 years, he faces the possibility of a challenge.
Many MPs, most notably fellow Conservatives, have turned against the MP for Buckingham. David Cameron is said to loathe him.
A committee overseen by Mr Bercow has opted to appoint Carol Mills, who heads the department of parliamentary services in Canberra, to replace the outgoing clerk, Sir Robert Rogers, on a salary of £200,000 a year.
But the appointment has caused a cross-party campaign opposing her appointment because some MPs feel the Australian lacks the necessary experience to oversee parliamentary procedure.