Schools with behaviour problems will face unannounced "dawn raids" by Ofsted from September to prevent them playing the system.
The watchdog believes that arriving without notice will help to give inspectors a clearer and more realistic picture of pupil discipline.
"If you know Ofsted is coming - even if it is just 24 hours before - behaviour is one of the things schools can quite quickly do something about," a spokeswoman said.
The new approach is being backed by the Government's new behaviour "tsar", Charlie Taylor. He believes some schools could ensure that their most difficult pupils are absent or being taught by very experienced staff when inspectors arrive.
But heads' leaders say there is no evidence of such malpractice and argue that the no-notice visits will be "fraught with difficulty" and achieve little.
Ofsted will be focusing the unannounced monitoring visits on around 500 schools judged to be "satisfactory" overall, with behaviour that is satisfactory or worse.
But only those where particular concerns about behaviour have been picked up through inspectors, exclusion data or parental complaints are likely to receive visits.
A trial will begin next term with a limited number of schools of all types in this category and will be extended if judged successful.
Ministers have long been keen to see no-notice Ofsted visits for schools with behaviour problems. Education secretary Michael Gove backed the idea while in opposition in 2009.
But Ofsted, which currently has no permanent head, said it was acting on its own initiative.
Miriam Rosen, the watchdog's interim head, said: "Where behaviour is poor, young people are being denied the quality of education they deserve.
"As we develop our new inspection plans, we are determined to get the focus on this right. By testing out unannounced monitoring visits, we will see if there is even more we can do to help schools address behaviour problems."
Charlie Taylor, the Government's expert adviser on behaviour, told The TES that he had heard stories of schools manipulating Ofsted.
"A couple of kids don't happen to turn up that day," he said. "You put the deputy head in to teach the difficult class rather than the supply teacher.
"I don't think it happens that much but we'll see.
"It's one thing putting on your best show, but it's another thing putting on a show that doesn't represent the school in real life."
Ofsted stressed that the plan was not a precursor to introducing no-notice arrangements to full school inspections, which had been included in 2007 plans for its current framework.
But it stepped back from the idea because parents had complained about not being able to make their views about a school known to Ofsted before an inspection.
Brian Lightman, Association of School and College Leaders general secretary, said: "We know that good behaviour is important but spot visits and making judgments based on a fleeting impression cannot be the best way to improving behaviour.
"I am not sure what this is going to achieve other than a culture which looks like it has been designed to try and catch schools out."
See next week's TES for an interview with Charlie Taylor.
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