Children's Commissioner for England Dr Maggie Atkinson has told ITV News that the murder of four-year-old Daniel Pelka is a "warning for us to keep vigilant".
Dr Atkinson added that information emerging from a review reveals that "signs were seen" over the abuse, "but was not followed through".
Questions have been raised over the murder of Daniel Pelka, after his mother and stepfather were jailed for 30 years today.
A couple have been jailed for a minimum of 30 years for murdering four-year-old Daniel Pelka, in March 2012.
A "callous and wretched" mother and her partner are facing life sentences for murdering systematically abused four-year-old boy.