Inspectors will be able to drop in on schools "on spec" after claims that heads send home disruptive pupils and poor teachers on scheduled inspection days.
Spot-checks are to be introduced by Education Secretary Michael Gove in an effort to improve behaviour. It will also be legal for students to be searched for phones, iPods, cigarettes and pornography. Headteachers will be able to take legal action against pupils who make false allegations about staff.
The proposals, which are subject to public consultation, could be in place by the start of the next school year.