Adoption of children from other countries also cannot be stopped because social workers do not agree with the idea of inter-country adoption, or if the child belongs to a different race or culture.
Paul Boateng, the Health minister, has issued guidance to help children left in care for too long because of "misguided practices" by social workers.
But social services chiefs said yesterday that while they welcomed a higher priority being given to adoption, a substantial proportion of adoptions were already transracial. Adoptions fell from 21,000 in 1975 to 2,300 in 1996, of which only 5 per cent were of babies aged under a year.
While Mr Boateng says that ethnic origin, culture and language are "significant factors" to be taken into account, "it is unacceptable for a child to be denied loving adoptive parents solely on the grounds that the child and adopters do not share the same racial or cultural background".
Banning prospective parents because they smoke is also "not appropriate and age must only be "one consideration amongst many" taken into account.
"For too long adoption has been regarded as the last and least acceptable option," said Mr Boateng. "Some local authorities still refuse to place children for adoption because one of the prospective parents is 40-plus, or is deemed the wrong colour, or smokes, or because of the belief that the family must be kept together, no matter what - even at the expense of the child's best interests. This shows a fundamental failure to understand the nature of adoption and its advantages for a child unable to live with his or her own family."
Last August, a report said that local authorities were providing a poor quality adoption service. Inspections of seven local authorities by the Social Services Inspectorate found the adoption process littered with avoidable delays, poor management and monitoring.
The new guidance says that social services directors will now be required to inform council members at regular intervals about the current position of children awaiting adoption. Senior managers must also review adoption services every three years, monitor the progress of recruitment of adoptive families, particularly from ethnic minority families, and review their polices in the light of this guidance.
Felicity Collier, director of British Agencies for Adoption and Fostering welcomed moves to put adoption higher up the agenda. She said: "We welcome anything which ensures every child has the opportunity for a loving family life when it is not possible to live with their birth family."
However, she said that it was a "myth" that black children languished in children's homes because same-race parents could not be found.
Ms Collier also added that new guidance was not enough. "We wish the Government to prioritise new legislation which is long overdue. Guidance is helpful, but what will make a difference is legislation."
Moira Gibbs, chair of the child and family committee of the Association of Directors of Social Services said that a 1995 BAAF survey showed 24 per cent of adoptions of ethnic minority children were transracially adopted.
She warned that talking of lifting bans could give the public the wrong impression. "The public have an out-of-date picture of adoption. I think this might encourage people with no prospect of adopting babies to think they might now be successful when there are tiny numbers available. It is not about banning people, but this will not increase the numbers of children available," she said.Reuse content