From September, people leaving the Royal Navy, Army and Royal Air Force who have a degree can enrol on teacher training programmes with an additional £2,000 bursary.
And from January, ex-service personnel without degrees will be able to enrol on a two-year, school-based, salaried training programme.
The latter group will become the only teachers who are allowed to train without a degree.
Schools minister David Laws said pupils would benefit from the “experience, background and skills” that ex-military personnel had gained during their tours of duty. He added: “We want to capture the ethos and talents of those leaving the armed forces, and bring this experience into teaching. We know that our highly skilled service men and women can inspire young people and help raise educational attainment.”
However, Christine Blower, general secretary of the National Union of Teachers, said that teaching had to remain a graduate profession. She added: “Teaching involves a complex mix of knowledge, skills and understanding of child development and trainees need both a high level of education themselves and thorough teacher training before they can take on the demands of educating our young people.
“This laissez-faire approach to the skills and knowledge necessary to teach children is quite shocking.”
Chris Keates, general secretary of the NASUWT, added: “Many ex-service personnel may want to become qualified teachers and they should be supported to go through the established routes to do this.”
Headteachers are also sceptical. Brian Lightman, head of the Association of School and College Leaders, said: “There is no doubt that some ex-military personnel have the potential to make excellent teachers, but they need the right preparation and support. From what we’ve seen so far, this programme is lacking in both.
“The government talks about creating a military ethos in schools. Ex-service personnel bring lots of relevant experience to the classroom, but a military ethos belongs in the military. Schools need a learning ethos.”
His counterpart at the National Association of Head Teachers, Russell Hobby, added: “We have been told constantly that subject knowledge and academic ability are essential pre-requisites for a teaching career. We cannot see how this scheme fits such a model.”
The Troops to Teachers programme comes at a time when the government is actively promoting a military ethos in schools. It has extended school cadet forces with 100 more schools being able to develop units by 2015, while a £1.5 million grant for charity SkillForce is paying for an extra 100 ex-service personnel to act as mentors to young people in challenging schools.