Teachers are being condemned to "pension poverty" after a lifetime of teaching the nation's children, a union leader has warned.
Dr Mary Bousted, general secretary of the Association of Teachers and Lecturers (ATL), urged MPs to listen to teachers' fears about the Government's public sector pension plans.
And she warned that ministers now only have a "small window of time" to engage and negotiate with the profession before they face the "massive impact" of a walkout by teachers.
Every school in England, Wales, Scotland and Northern Ireland could be closed on November 30 if teachers and lecturers take part in the TUC's day of action.
Dr Bousted was speaking as members of seven teaching unions began a joint lobby of MPs at Parliament - the latest salvo in the bitter row over public sector pensions. She said teachers are concerned that the plans will leave them working longer, paying in more and receiving less when they retire.
"They are saying that they simply can't work until they are 68 - can you imagine a classroom of 30 children with a teacher of 68?" she said. "They don't see why they need to bail out the bankers and pay 50% more for their pensions.
"And they don't see why they are going to end up in retirement with a pension that's much worse than the one they have currently got. It is condemning teachers to pension poverty."
The average teacher's pension is £10,000, Dr Bousted said, "after a lifetime of service to the nation's children. These are not gold-plated pensions."
Ministers have insisted that changes to public sector pensions are necessary to ensure they are sustainable for the future.
"We hope ministers, the Government and MPs will listen to our case", Dr Bousted said, later adding "they have a short window of time to turn this around now".