A newborn baby found earlier this year in Newham, east London, is the third child abandoned by the same parents, the BBC can report.

DNA tests presented to the East London Family Court established that “Baby Elsa” is the sibling of two babies, a boy and a girl, found in very similar circumstances in 2017 and 2019.

Despite appeals by the Metropolitan Police, their parents have not been identified.

The BBC and PA Media were given special permission by the court to report the sibling link – and that the children are black.

Judge Carol Atkinson said the story was of “great public interest” as babies are very rarely abandoned in modern Britain.

An expert told the court that, in his opinion, the genetic findings provided extremely strong scientific support for the view that Baby Elsa was “a full sibling” of the other two babies.

The older children have been adopted and Baby Elsa remains in foster care.

She was found by a dog-walker in January in sub-zero temperatures – the coldest night of the year – wrapped in a towel inside a bag.

The other babies – named Harry and Roman – had also been abandoned after birth in the same area of London.

They had been wrapped in blankets. One was also inside a bag.

Family Court documents stated Baby Elsa still had her umbilical cord, and doctors estimate she had been born only an hour before.

Although she was extremely cold when found, Elsa was described as crying and responsive. The court has since heard that she is doing well.

The Family Court has heard that the children – whose names have now been changed – will all know that they are full siblings, and there are plans for them to have some form of contact as they grow up.

The reporting of the sibling link was not supported by the local authority and England’s Children and Family Court Advisory and Support Service (Cafcass), which advises courts about children’s best interests.

The Met Police said it was up to the court to determine whether the link between the children should be reported, but they told the court they did not wish to “inadvertently promote or encourage struggling mothers to abandon unwanted babies in public spaces”.

East London Family Court is taking part in a transparency pilot, which has been extended to cover almost half the family courts in England and Wales. This makes it easier for the BBC and other journalists to report cases.

The BBC and PA Media argued in court that it was a matter of public interest that the three children had been abandoned at birth by the same parents.

Carol Atkinson, the most senior judge in East London Family Court, agreed.

“Abandonment of a baby in this country is a very, very unusual event,” she said, adding that there was considerable public interest in such cases, for that reason.

She said the fact the three babies were full siblings was, for the same reason, “of enormous interest” in “our current society”.

She said that if she were to refuse reporting, it would affect the “public consciousness” of these matters, and restrict open justice in such cases.

The BBC and PA said further reporting was likely to assist the authorities in locating the children’s parents, and that highlighting the relationship would put the focus back on the children’s mother.