A social worker has been struck off for showing "extremely poor judgement" in dealing with a case in which a 13-month-old boy was later murdered.
Eleni Cordingley, who worked for Swansea council, will no longer be able to practise after admitting misconduct to the Care Council for Wales.
A conduct hearing was told she did not follow child protection procedures in the case of Aaron Gilbert.
Aaron died from brain damage in May 2005 after he was badly beaten.
Andrew Lloyd, his mother's boyfriend at the time, was jailed for a minimum of 24 years for the baby's murder.
His mother, Rebecca Lewis, was found guilty at Swansea Crown Court of familial homicide and jailed for six years after the jury heard she failed to prevent her son's killing.
After appearing in front of the conduct committee hearing in Cardiff, Mrs Cordingley was told she would no longer be able to practise as a social worker anywhere in the UK.
The committee was told that the access and information team at Swansea Council's social services department had received two anonymous calls from the same person expressing concerns about Aaron's family.
Throughout the hearing he was referred to as child A.
The committee ruled: "In failing to act appropriately in response to the complaints between 27 April and 5 May 2005, you are guilty of misconduct by putting Child A at risk.
"By exercising extremely poor judgement you failed to work in a safe and effective way.
"The misconduct admitted in this case is considered to be so serious that removal from the register is the only appropriate sanction.
"This is necessary for the protection of the public and to uphold the public interest in maintaining confidence in social care services."
The committee also expressed concern about the delay in Swansea council informing the Care Council for Wales about the result of a disciplinary hearing for Mrs Cordingley concluded in October 2007.
A council spokesman said: "The death of Aaron Gilbert in 2005 was a terrible tragedy and Swansea council is very sorry that it happened.
"We informed the care council that an internal disciplinary hearing was being held.
"Unfortunately, there was an oversight in not informing them of the outcome until February 2008 and we apologise for the delay.
"Following the care council's decision we have taken immediate steps to suspend the social worker.
"We will also need to consider what further action may be necessary in the light of the evidence and outcome of the care council hearing."
Following Aaron's murder a serious case review looked at all the circumstances surrounding his death.
"It found that prior to the first anonymous phone call, Aaron was not known to social services. He was not on the at-risk register," added the council spokesman.
"However, it concluded that all the agencies involved with the family had important lessons to learn and made recommendations on how these should be implemented.
"Since that time we have implemented all of the recommendations in the LSCB [Local Safeguarding Children's Board] report.
"Within child and family services we have also taken independent expert advice and worked with the Care and Social Services Inspectorate Wales to strengthen and improve our services to vulnerable children."
The council said that this year alone it had spent more than £350,000 to recruit additional social workers.
Cabinet member of social services Wendy Fitzgerald said: "We have improved services and will continue to work with the Care and Social Services Inspectorate to bring further improvements.
"We will be looking at the evidence and outcome of the CCW hearing and considering what further actions are necessary."