The death of Keanu Williams in 2011 is one of a number of high-profile cases in Birmingham
More work is needed to protect children in Birmingham, according to the commissioner appointed to oversee the children's services department.
Lord Warner was named by the government 12 months ago after years of the department being rated inadequate.
In 2013, it was branded a "national disgrace", but last year the council pledged £9.2m to improve practices.
Lord Warner said there had been "significant improvements", but more was needed.
Since 2006 there have been 24 serious case reviews in the area.
"I think they're safer than they were 12 months ago and certainly Birmingham City Council has put a lot more money into those services, not before time I might add, but they're not as safe as they could be," he said.
"The issue is around have they got enough social workers, particularly enough experienced social workers, and is the social work practice good enough? And the answer to both those questions is it's not good enough yet.
Lord Warner was appointed as commissioner for Birmingham children's services in March 2014
"They've made children's services the top priority for the council and at a time of great financial hardship they've committed to big increases in the funding for children's services all the way up to 2017 and 18."
He said changes meant the council, the local NHS and police were all working much better together and there were about a third more children being referred than a year ago.
Despite offering increased salaries, the council said earlier this month it was still struggling to appoint enough experienced staff.
"What's happened since last year, when I arrived, is certainly Birmingham has improved the front door - the people who receive the referrals and the contacts of which children are at risk," Lord Warner said.
In August, Bernadette McNally was appointed to take over running children's services in Birmingham, but in October she said she was no longer interested in the role.
An interim boss was found and in February Alastair Gibbons took over as executive director, the fourth since 2009.
Despite the "hiccup" surrounding Ms McNally's appointment, Lord Warner said improvements had also been made in management.
However, he said changing the culture would "take time".
The peer is due to finish his time as commissioner to Birmingham's children's services at the end of May.