Stephen Dorrell, the Secretary of State for Health, told the Association of Directors for Social Services annual conference that ministers would tighten the law and extend regulations on registration to homes with less than four children.
The move was announced amid a rise in the number of small homes for children, and increasing concern about abuse. Last year, a highly critical report by the Social Services Inspectorate warned that lack of registration in privately run children's homes meant that sex abusers have been able to set up institutions, with local authorities often taking a "lax approach" to investigating them.
The inspectorate said that in some small homes it found fraudsters working, and people subsequently convicted of sexual and physical abuse. At present, small homes do not have to register under the 1989 Children's Act, nor are they obliged to carry out police checks.
"It is anomalous that [these homes] should be exempt from registration," said Mr Dorrell, "particularly in a field where the risks of abuse are well-known."
Changes in social services over recent years meant the regulatory system, aimed at protecting vulnerable people, was out of date, he said.
His speech came as a report was published on the regulation and inspection of social services. The study, by a former civil servant, Tom Burgner, makes a number of key recommendations, including calls for trading standards or councils' chief executive departments to take over responsibility from social services for inspecting care homes.
"It seems clear that there is a gap in regulatory arrangements that leaves vulnerable children at risk," says the report. "The absence of a requirement to register is a fundamental handicap in ensuring that an adequate standard of care is being provided."
Mr Burgner added that local authority homes should be subject to the same rules as homes run by the voluntary and private sector, and that there should be new national benchmarks on standards for homes operated by councils and others.
Mr Dorrell said that the Government had accepted these recommendations and that a White Paper aimed at closing gaps would be published in January. "We are committed to promoting and defending high standards of professional practice," he told the conference in Edinburgh. "The time is right for further development of practice and conduct standards."
Mr Burgner's report also covered the regulation of residential care and nursing homes for the elderly, suggesting that the legal distinction between the two should be abolished.
"Our initial view is that the case for this kind of "single care home" has not been convincingly made," said Mr Dorrell. "But we want to hear what others think about this key issue."
Counsel and Care, the charity which gives help to older people, urged the Government to go further on inspection for homes, saying the announcements were "inadequate".
"We welcome the Government's announcement," said Jeff Smith, the charity's general manager. "But those outlined do not go far enough. There needs to be a new, tougher system to promote high and consistent standards of care and to span the current professional split between residential care and nursing homes."Reuse content