Under British law and accordingly,
The Child Welfare Act 17, 1939:

The mother was the sole legal guardian of her child until the adoption order was made through the Supreme Court. This meant that she could legally reclaim her child from the foster parents at any time prior to the adoption order being made if her circumstances changed. The placement of a child with adopters was merely an interim placement and was not legally binding.

Most mothers knew nothing of their right to reclaim their child. Most are still unaware.

Nevertheless, as adopters began to claim how they could not bond with the child with the threat of its mother returning to reclaim her child, to alleviate any greater stress than necessary on the adopters, the new Adoption of Children Act would introduce into legislation a clause to reduce the mothers revocation period to a maximum thirty days. But again many mothers were never informed of the newly introduced revocation period.

The Adoption of Children Act 1965, proclaimed on 7th February 1967

Because of the permanent nature of adoption, the revocation period was essentially meant to be a cooling off period. Its intention was meant to ensure that the mother was fully aware of her actions, and if she decided life would be too unbearable without her child she then had time to revoke her consent. It was also meant to give her time to recover from the birth and get her life in order before she made such a life altering decision as surrendering her child.

Still in a state of unspeakable trauma in having been forbidden to see her child or at best offered a glimpse, and having been counselled into believing her child did not belong to her, thirty days was hardly enough time to recover from the birth let alone find employment, accommodation and childcare while still attempting to recover from her experience. Although unbeknown to her, these facilities had been readily available and she was supposed to be made aware of such help as part of her so-called counselling interviews.

Although a mother was meant to be able to reclaim her child within the 30 day revocation period, few ever managed to access that legal right unless their parents were willing to support them, even if the mother was already an adult and in her twenties.

Too late most realised that the thirty day revocation period was being used simply as a trap to ensnare those who tried resist into signing a consent, believing she had time to get help and her life in order and come back for the child. But with the baby being already allotted, by the time she returned, they had no intention of giving her child back.

Additionally, because mothers were not being made aware of how to go about revoking her consent to reclaim their babies within the legally permitted time, she had to re-contact the staff of adoption agency or hospital who had taken her consent, and in doing so would be routinely obstructed from revoking, being met with resistance, and hindered from carrying out her original intention by being told it was all too late and too bad.