THE terms of the Scottish Child Abuse Inquiry should be expanded to include hundreds of boys and girls forced to emigrate into the Commonwealth following the First World War, former prime minister Gordon Brown has urged.

Between 1920 and 1970, more than 150,000 so-called child migrants are thought to have been sent from the UK to Australia, New Zealand, Zimbabwe and Canada under a policy Mr Brown described as “callous”.

The children were removed to destinations they did not know, sometimes without consulting their parents, while some were wrongly told they were orphans.

More than 4,000 children aged from three to 14 were forced to migrate in this way after the Second World War.

In 2000, Mr Brown apologised for the deportations on behalf of the British people, but said it was now apparent that hundreds had been left vulnerable to sexual abuse and others had been abused before they left Britain.

In a new statement, the former prime minister revealed he had written to the chair of the UK's Independent Inquiry into Child Sexual Abuse urging action but claimed the Scottish equivalent but must also examine the claims.

He said: "Approximate 200 Scots boys and girls were child migrants.

"The separate Scottish inquiry into sexual exploitation, chaired by Rt Hon Lady Smith, should make this a subject of their investigations.”

Much of the evidence for the former Labour leader’s claims has come to light in the Australian Royal Commission on Child Abuse.

“First, scores of children were themselves subject to abuse before they were deported to foreign countries," he said. "Indeed, some may have been deported to hide evidence that crimes had been committed against them in this country.

“Some of the children sent to Australia had already been subject to molestation in children’s homes in Britain. They were being sent abroad to get them out of the way to be subjected to further abuse as part of a cover up of abuse already inflicted on them in Britain.

“Second, hundreds of children who were themselves stigmatised as child migrants and separated from their family and country were also abused in the children’s homes and orphanages to which they were sent,” he said.

Mr Brown cited the experience of one child who was abused in a UK children’s home from the age of five.

“He would come and get me night, he would grab me, put his hand over my mouth punch me hard in the stomach so I couldn’t struggle," he wrote. "Sometimes he would take me down to the cellars where they kept the sick children. Dark, windowless rooms with only a hall light outside. It was a scary place. I was sent as a child migrant to Australia where the abuse started again.”

While the justification at the time had been that poorer children were being sent to a "better life", the true picture was more complex, Mr Brown said.

“Perhaps most insidious of all, we now know some church and charity leaders came from Australia to Britain to handpick British boys for their own gratification through systematic molestation," he said.

Even in the late mid-1950s when the UK and Australian governments clearly had evidence that abuse was happening, they did nothing, he said, which amounted in his view to criminal negligence.

He said that the Child Migrants Trust should help former child migrants who are still alive, but it has no resources as its funding expires in March 2017. “Cutting off the fund now would be cutting a lifeline for the children we abandoned. And this policy must be reversed,” he said.