Elsa was found wrapped in a towel in a reusable shopping bag on January 18, 2024, at the junction of Greenway and High Street South in East Ham.
Elsa – named after the Frozen character – was believed to be less than an hour old when she was found by a dog walker.
In the months that followed it was found that she had two siblings who were also abandoned, in 2017 and 2019.
In September 2017, Harry was found wrapped in a white blanket in Balaam Street, Plaistow.
Roman was found in similar circumstances in a play area off Roman Road, Newham, in late January 2019, as freezing temperatures and snow gripped the city.
Harry and Roman, not their real names, have since been adopted.
The police investigation into the identity of her parents remains ongoing, and a £20,000 reward is offered for information leading to their identification.
At a hearing earlier in February, East London Family Court was told that Elsa had taken her first steps and was “developing well”, which Judge Carol Atkinson said was “astonishing”.
Steven Evans, for Newham Council, said: “The social work team reported to me that Elsa is developing well. She has taken her first steps. She is meeting all her developmental milestones.
“The social worker describes her visits as ‘the best visits ever’.”
The Metropolitan Police previously said more than 450 hours of CCTV had been reviewed as part of its investigation.
A spokesman for the force said that the probe remains ongoing and that detectives “have been working with subject matter experts at the National Crime Agency as part of this investigation”.
On the first anniversary of Elsa’s discovery earlier this year, the independent group Crimestoppers offered a £20,000 reward for information passed to the charity, which will expire on April 18.
The police investigation into the identity of the children’s parents continues, and anyone with information is asked to call police on 101 or post @MetCC ref Operation Wolcott.
People can also contact Crimestoppers anonymously at any time on 0800 555 111 or via Crimestoppers-uk.org.
The reward will only be payable for information passed directly to Crimestoppers and not to the police, and a reward code must be asked for.
Those who contact Crimestoppers online must use the “keeping in contact” facility, and a reward code must be requested.
