Gordon Brown is set to apologise on Wednesday for the UK's role in sending tens of thousands of children to former colonies where they suffered terrible abuse.
The Prime Minister is due to express the Government's regrets over the child migrants programme in a statement to the House of Commons.
Under the scheme, which ran from the 1920s to the 1960s, an estimated 150,000 poor youngsters aged between three and 14 were sent to a "better life" in Commonwealth countries such as Australia and Canada.
However, many ended up being abused in foster homes, state-run orphanages and religious institutions.
Children were often told their parents were dead, while parents were given very little information about where their offspring were going.
Survivors have told how on arrival they were separated from brothers and sisters, and subjected to brutal physical and sexual abuse by those who were meant to be caring for them.
The premier's spokesman said the issue is something he feels strongly about. Mr Brown announced he was planning to apologise in November when Australia's prime minister Kevin Rudd said sorry for his country's part in the tragedy.
Britain's High Commissioner to Australia, Baroness Amos, said in a statement last week that the apology would be an "important milestone".
Harold Haig, Secretary of the International Association of Former Child Migrants and their Families, said: "For many former child migrants and their families, the apology will help to heal a painful past."
The wording of the apology by Mr Brown is believed to have been discussed with charities representing former child migrants and their families. Sixty survivors have apparently been flown to London so they can listen to the statement in person.