Inspectors are to reduce the notice they give to nurseries after a BBC documentary showed children being shouted at and poor hygiene in an undercover operation.
The documentary, Nurseries Undercover: The Real Story, showed carers berating young children and exposed the under-staffing at some establishments.
The nurseries involved were Little Treasures in Festival Way, Stoke-on-Trent, Petits Enfants in Church Road, Teddington, south-west London, and Bank House day nursery in Radcliffe, Greater Manchester. Four staff have been sacked by Little Treasures, the BBC said.
Early-years providers will be told which month inspectors will visit, but not the week or day.
The Office for Standards in Education said it could carry out unannounced inspections if it believed standards were not being met. In the year until April 2004, it made 3,500 unannounced visits.
The process to cut notice for inspections began in February. This week, Ofsted said that it had "discussed this issue with its National Consultative Forum and has received no opposition to reduced notice for inspection of group day care". It said reduced-notice inspections will begin in April 2005, but the new notice period is yet to be decided. It said it was "disappointed" that it had not been informed about the documentary after filming was completed earlier this year. It became aware of the programme only when a parent in Stoke-on-Trent made contact four months later.
A BBC spokeswoman said: "We gave Ofsted six weeks' advance notice before transmission of the allegations and the programme included detailed comments from Ofsted."