Gordon Brown will apologise to half a million children sent abroad to a life of slavery

The Prime Minister will express regret and sorrow in a Commons statement designed to help heal the wounds of people sent thousands of miles from their families.

About 60 former child migrants will be in the public gallery to hear the apology, some of them only recently reunited with siblings and parents they had not seen since childhood.

Under the Child Migrants Programme — which ended just 40 years ago — 500,000 poor children from orphanages and foster homes were sent to a "better life" in Australia, Canada and elsewhere.

However, many were abused in remote settlements and were used as free labourers on farms. Among those flying to London to hear the Prime Minister speak is Marcelle O'Brien, who endured a childhood of poverty, brutality and sex abuse after being sent to Australia in 1949, aged four.

She was taken from a foster family, despite their protests, and placed on a farm in the outback with other girls who were forced to work without shoes or coats, even in winter. She recounts physical and sexual abuse.

"I lost my whole childhood and with it my sense of hope and joy," said Mrs O'Brien, 65. She was put into domestic service at the age of 16 and had to live under a garage. She was raped by three men but the authorities took no notice.

After 40 years, in which she married, had four children and divorced, Mrs O'Brien was tracked down by her foster sister, Beryl, through the Child Migrant Trust, a charity set up to help the victims of the scheme. Then in 2002, the trust helped her to find her natural mother who had not seen her since she was a baby.

Her mother's first words to her were, "I know who you are Marcelle — the bastards took you."

Mrs O'Brien said: "It's hard to describe what it felt like the day I met my mother. I just held her in my arms, and perhaps a little of the hurt began to melt away. My mother was then quite frail and I didn't have her for very long. But now I have an identity and that can never be taken from me again."

Of tomorrow's apology, she said: "It feels too late but it's important that we accept it."

It took 62 years to find my mother'

John Hennessy, originally from Cheltenham, was shipped out in 1947, aged 11, to Bindoon Boys Town, Australia. His mother was found by the Child Migrants Trust in Surrey in 1999 and they were finally reunited. He helped make the case for tomorrow's apology.

"I was illegally deported to Australia without my mother's knowledge or consent," he said. It took me 62 years to find her after being deceived that I was an orphan — an outright lie. My mother and I had six short years together out of a lifetime of loss and loneliness."

He recalled being put in a truck with other screaming children by Christian Brothers. "Punishments were done as public spectacles, causing children to wet themselves in fear," he said. "Flogging with canes and belts until we fell to the ground, bleeding. Most of the Christian Brothers were paedophiles."

Mr Hennessy built up a painting and decorating business and became deputy mayor of Campbelltown.

Authorities deported me to hell'

Bill Malone, born in West Ham in 1945, was sent from St Joseph's Orphanage in Enfield, also to Bindoon Boys Town, aged nine, without his mother's knowledge.

Aged 10, he was bringing in the farm harvest as an unpaid labourer. He had no proper education and, barely literate, was forced into low paid jobs as an adult. He was told that he was "a bastard from England". Only on being reunited with two sisters, aunts and cousins a year ago did he learn the truth.

"My dad died from TB when I was very little and my mum got into hard times," he said. "Instead of supporting a family in need, the authorities split us up and deported me into hell."