Education Secretary Michael Gove launched a broadside at union leaders today - accusing them of "wanting" to wreck economic recovery and cause public misery.
He said at least 90% of schools would be closed on Wednesday as part of the biggest day of strike action in more than 30 years, over public sector pensions.
And he made a last-ditch appeal to teachers to "pause and reflect" before joining the mass walkouts, insisting they were being offered a "good deal" by the Government.
In an outspoken intervention in the bitter dispute, he said it was "unfair and unrealistic" to expect taxpayers to foot the increasing bill for pensions.
"On Wednesday, TUC leaders will call on their members to bring Britain to a halt.
"Among those union leaders are people who fight hard for their members and whom I respect. But there are also hardliners - militants itching for a fight.
"They want families to be inconvenienced. They want mothers to give up a day's work, or pay for expensive childcare, because schools will be closed.
"They want teachers and other public sector workers to lose a day's pay in the run-up to Christmas.
"They want scenes of industrial strife on our TV screens, they want to make economic recovery harder, they want to provide a platform for confrontation just when we all need to pull together."
Mr Gove spoke of his own experience as a journalist involved in a strike called by union leaders to "prove a point".
"I lost my job. So did more than 100 others. I was lucky - young, unmarried, without a mortgage. I got another job soon enough.
"Many others didn't. They never worked again in the profession they loved. And the deal we were offered before the strike never improved.
"So today I want to appeal directly to teachers - and other public sector workers - please, even now, think again."
The Education Secretary said it was a "myth" that he wanted to force every teacher to stay in the classroom until they were 68.
Asked if he included teachers' unions among his "hardliners", Mr Gove said: "I do not hang that badge around the necks of any teaching union leader."
He named other union leaders, including Mark Serwotka of the Public and Commercial Services Union (PCS), Len McCluskey, of Unite, and Andrew Murray, also of Unite, as people for whom "militant is a badge that fits".
Answering questions after the speech, Mr Gove said: "You have only got to look at the words of Len McCluskey in the Guardian today, consider the conduct of Mark Serwotka throughout this dispute or look at the political record of Mr Andrew Murray, who is a lead official in Unite, to recognise that 'militant' is a badge that fits for all those three."
He indicated that he wanted reforms to strike laws to be considered to give headteachers more notice of whether they would be able to keep their schools open.
At present, individuals are not obliged to inform their school that they intend to join the walkout until the day of the industrial action.
Calls for reform have centred on the need for a union to have at least half of eligible members backing a strike, rather than just a majority of those taking part in a ballot.
Mr Gove noted that, while all legislation remained open, teaching unions had demonstrated "clear" concerns over pensions among their members.
But he added: "One of my concerns is that you do not have to give notice directly to your employer that you will go on strike. You need simply to inform them on the day.
"I think that contingency planning in many cases is made more difficult by that."
Aides indicated that the lack of notice created havoc in trying to establish which schools would be open and meant predictions of the numbers closed were an educated guess.