A television documentary on forced marriages served as the catalyst that prompted one of the three women rescued from a South London house to call for help, police said.
'Exposure: Forced to Marry' was broadcast on ITV on October 9.
An investigation carried out for the programme found that religious leaders at some British mosques seemed willing to perform underage marriages. Some 18 of the 56 mosques contacted by undercover reporters working on the documentary agreed to perform the marriage of a 14-year-old girl.
Nazir Afzal, chief crown prosecutor for the CPS North West, told 'Exposure' that "forced marriage is probably the last form of slavery in the UK".
The programme also featured the work of Freedom Charity, which was established to raise awareness about children and young people who are at risk of, or subjected to, violent crimes, dishonour-based violence and forced marriages in the UK.
According to its website, its stated aim is to "empower young people to feel they have the tools and confidence to support each other and have practical ways in which they can help their best friend around the issues of family relationships which can lead to early and forced marriage and dishonour-based violence".
The charity's founder, Aneeta Prem, appeared on the ITV programme, after which the Irish woman who was among the three was said to have made a phone call to the charity.
It was this call that led to the eventual rescue of the women after the charity alerted police.
Ms Prem said: "I think all of them saw me on the news and made a decision because of the name of the charity and because they had seen me on TV – that gave them the courage to make that phone call.
"I can't go in to too many details but they managed to get to a phone and make a call to us.
"We started to talk to them in depth when we could. It had to be pre-arranged when they were able to make calls to us and it had to be done very secretly because they felt they were in massive danger.
"It was planned that they would be able to walk out of the property. The police were on standby." (© Daily Telegraph, London)