Plans to force children as young as 10 to wear electronic tags to keep them in school are "draconian", say teachers' union leaders.
They warned that the tags would be regarded as "trophies" by juvenile offenders and would encourage further lawbreaking.
Ministers want courts to be able to impose curfew orders backed by tagging, now being tried in three counties for over-16s, to punish juvenile criminals aged 10-15.
Home Office minister David Maclean put forward plans to extend trials for the tags in an amendment to the Crime (Sentences) Bill now going through Parliament.
He said: "We believe that curfew orders could keep young offenders off the streets . . . they could be ordered to stay at home at night or at certain times during the weekend. They could also be required to be at school during school hours."
But Nigel de Gruchy, general secretary of the National Association of Schoolmasters and Women Teachers, said: "It seems draconian and I'm sceptical that it would work. It would be like giving youngsters a badge of dishonour which they would wear with perverted pride."
The curfew orders, lasting up to three months, are expected to be used mainly for children who have repeatedly been involved in crimes such as shoplifting and vandalism.
The National Union of Teachers said there were better ways of making sure that children attended school.