Ofsted has announced it is to initiate a round of no-notice inspections across schools around England.
These are to be conducted on around 40 schools during a two-week window in September, under powers already available to the inspectorate.
The inspection body's actions follow recent events in some schools in Birmingham, which have been placed in special measures after leadership, governance and safeguarding concerns were raised.
Chief inspector Sir Michael Wilshaw has agreed to examine the feasibility of moving from the current practice of allowing schools half day's notice to carrying out inspections on all institutions without warning.
In the meantime, Ofsted's regional directors have been instructed to make wider use of existing powers to conduct no-notice inspections of schools where there are concerns about safeguarding, standards and the curriculum.
Declining standards, leadership or governance problems, safeguarding issues - including concerns about behaviour and discipline - and concerns about the breadth and balance of the curriculum will all be reasons for the inspections to be carried out.
Section five inspections were already scheduled to take place in many of the institutions selected for the no-notice round. However, additional schools are to be included where Ofsted has become aware of new concerns.
Sir Michael Wilshaw, said: "Parents rightly expect Ofsted inspections to get to the heart of any problems that may exist in a school - whether they are to do with discipline, safeguarding, poor leadership or governance, or a narrow, unbalanced curriculum.
"That's why we've expanded the criteria for conducting unannounced inspections for the coming year."
Unannounced inspections will continue to take place throughout the academic year. An early assessment of the impact of the no-notice round will be carried out after the two-week window of inspections is completed.
Regular monitoring visits are being carried out by Ofsted's inspectors on the institutions in Birmingham placed in special measures in June. Sir Michael recently visited one of these institutions, Park View Academy, to assess the impact of its school improvement plan.
Posted by Harriet McGowan