Schools in England are to get new powers to punish pupils who behave badly on the way to and from school.
Ministers want to tackle poor behaviour
Pupils misbehaving on buses and trains or in the street will be targeted under the moves, which form part of the prime minister's "respect" agenda plans.
Teachers will also be given the right to confiscate pupils' mobile phones or music players if they hinder learning.
Schools Minister Jacqui Smith set out the details at a conference in London on Wednesday.
Ms Smith said: "A culture of disrespect and failure to take responsibility will not be tolerated."
Many head teachers already operate a system of pupils being regarded as "ambassadors" for their school while they are dressed in uniform outside the school gate.
But, under the government plans, teachers would have their powers to discipline pupils who misbehave on the way to and from school strengthened, with a legal right to take action.
The proposals on discipline, outlined in the government's education White Paper, reaffirm the existing statutory right to physically restrain pupils to stop them hurting others or themselves.
The government is also placing more onus on parents for their offspring's behaviour.
Parents will be forced to take responsibility for excluded pupils in the first five days of their being suspended from school.
Ms Smith said it was easy to forget that pupil behaviour in the majority of schools was good for most of the time.
"Ofsted has reported improvements in behaviour in our classrooms this year, rating it as satisfactory or better in 94% of secondary and 99% of primary schools," she said.
"But it takes only a handful of poorly behaved pupils to make life difficult for teachers and disrupt the education of other pupils.
"Our White Paper proposals will strengthen teachers' authority, and give them the confidence to take firm action on all forms of bad behaviour."
The National Union of Teachers said the unambiguous right for teachers to discipline pupils was welcome and long over due.
"Teachers need to be absolutely confident about their authority," said general secretary Steve Sinnott.
"To enshrine a teacher's right to discipline pupils in law will reinforce the message to parents and the wider community that schools are safe and secure places of learning."
Head teachers' doubt
But a small-scale survey of senior school staff found many were sceptical that proposed extended powers to restrain unruly pupils would make much difference.
A poll of 100 members of the Association of School and College Leaders found only 13 thought the moves would help significantly.
A majority - 59 - said the measures would have some impact on behaviour, but 28 said they would have no impact.
One head teacher responded: "All new measures will help, but government diktat will help with behaviour no more than it helps with other issues."
Another said: "The real issue is one of resources. Poor pupil behaviour requires specialist input to resolve it. That means specially trained staff and alternative learning opportunities."
A Department for Education spokesman said: "Even in this very small poll it is clear that the majority - 72% in this case - recognise that the legal right to discipline will have an impact in tackling poor behaviour.
"It will play a key part in reinforcing the authority of teachers in the classroom and send a strong signal to pupils that bad behaviour will not be tolerated."
Bad behaviour 'on the decrease'
The details of the discipline measures come as a survey from the teachers' union NASUWT found bad behaviour in classrooms was in decline.
The union compiles details of the number of members holding a "refusal to teach" ballot on particularly unruly pupils.
It found just 13 ballots were held between September 2005 and February this year, compared to 20 over the same period in 2004-05.
"Although there is certainly no room for complacency and the problem of pupil indiscipline is far from being resolved, the latest figures suggest the start of a welcome trend in the right direction," said the general secretary, Chris Keates.