From May this year Ofsted and the Care Quality Commission (CQC) will assess how well nurseries, schools, colleges and health and care services identify, meet the needs of, and improve outcomes for children with SEN.
It had initially been planned to give services two days' notice prioir to inspection, but following a consultation on the proposals, Ofsted and CQC said this will be extended to five days.
The inspectorates said the move will “ensure all partners, especially young people, parents and carers, have ample opportunity to offer their views about local education, health and social care services, and fully engage in the inspection”.
The Association of Directors of Children's Services has previously said that the remit of the inspections is too broad and have questioned how they would be completed in the required timeframe of one week.
But Ofsted said that, out of around 2,000 responses to the consultation, almost 90 per cent of respondents were supportive of the proposals.
Joanna Hall, Ofsted’s deputy director for schools, said the inspections are likely to uncover some "hard truths".
“However, I want to stress that our inspection reports will also highlight effective practice," she said.
"It is my hope that other local areas will learn from examples of how things can be done well so that there will be a long-term cultural change in the way these services are delivered.
“I believe that the inspections will help local areas improve the services they deliver to children and young people with special educational needs or disability.
“These inspections will also provide reassurance to families, children and young people that local areas are being held to account.”
Steve Field, CQC's inspector of general practice, said that the inspections will help give examples of good practice to underperforming areas.
“Children and young people with special educational needs have the right to access the support they need from local health services,” he said.
“This critical work will for the first time highlight whether these needs are being met and while there could be some uncomfortable truths coming out of this work, we also aim to shine a spotlight on those local areas that are performing well to help services improve nationally.”