Alec Smith, school board chairman, confirmed the 280-pupil secondary would continue the fight to avoid closure. It is the first school to seek a second ballot on self-governing status after the Scottish Secretary turned down its first application more than two years ago.
Events quickened this week after the council's legal advisers pointed out that the board had run out of time to hold a ballot. Glasgow is therefore planning to close the secondary at the October holidays and merge it with the already overflowing Holyrood, Scotland's largest secondary.
The John Bosco board, however, insists its ballot is legal and has been encouraged by the Scottish Office, which is footing the electoral bill, to press ahead, despite overstepping the three-month period within which voting normally takes place. It blames inaction on the summer holidays.
Parents are now to seek legal advice about the validity of the ballot and charge the council for what they consider is a legitimate activity.
Meanwhile, education officials are to hold talks with the headteachers of Holyrood and John Bosco to phase in amalgamation and establish ways of using both buildings to accommodate the increased numbers. The merged school is set to be named Holyrood and run by Finbar Moynihan, its current head.
The city council is expected to ratify the John Bosco closure at its meeting on September 25.