(CNN) A woman found guilty of taking her 17-year-old daughter to Pakistan for a forced marriage was sentenced Wednesday to four-and-a-half years in prison by a British court following a landmark conviction.

The teenage girl, who cannot be named for legal reasons, was taken to Pakistan by her mother under the guise of a holiday, but later found herself being forced to marry a relative almost twice her age.

The mother, who has three other children, was convicted on Tuesday at Birmingham Crown Court on charges of deceiving the victim into traveling to Pakistan in order to enter into a false marriage, forced marriage and perjury.

It was the first time a conviction has been secured after a victim testified against her own family. Legislation against forced marriage was introduced in the UK in 2014, but has led to only one previous successful prosecution.

Nearly 1,200 possible forced marriages were flagged up to British authorities last year. According to a UK government report, the statistics do "not reflect the full scale of the abuse."

Pregnant at 13

The court heard that the girl had been entered into a "marriage contract" with the man years before in Pakistan and became pregnant to him at age 13. The victim had an abortion on returning to the UK, with her doctor reporting his concerns to social services.

The girl's 45-year-old mother, who cannot be named for legal reasons to protect the identity of the victim, tricked her daughter into returning to Pakistan shortly before her 18th birthday.

Figures published last year by the United Nations' International Labour Organization (ILO) showed 15.4 million people across the world were trapped in a forced marriage in 2016.

In 2015 and 2016, the UN Human Rights Council adopted resolutions calling for an end to child, early and forced marriage, and recognizing child marriage as a violation of human rights.

'Culturally embedded'

Prominent Pakistani activist and writer Bina Shah said the problem of forced marriage was culturally embedded in Pakistan, with marriage seen as transactional and girls often considered as commodities.

"It is a major problem in Pakistan. We have the problem of child marriage but also coerced marriages, which, given that most marriages in Pakistan are arranged, is widespread," she said.

The marriages are often made between relations, particularly in rural areas, to keep property in the family, she added.

"People are looking for other advantages, for example, to marry someone with a foreign passport," she told CNN.

Shah pointed to a case of an Italian girl of Pakistani origin who was rescued from the prospect of a forced marriage last week after she had been lured to the country by her family on false pretenses.

"Violence against women and girls -- including rape, murder through so-called honor killings, acid attacks, domestic violence, and forced marriage -- remained routine," said a Human Rights Watch report on Pakistan published last year.

Repatriation

The Birmingham court heard that the victim had been returned from Pakistan to the UK with the assistance of the Home Office.

The Forced Marriage Unit, a joint team from the Foreign and Commonwealth Office and the Home Office, was set up in the UK in 2005. It provided support to about 1,200 potential cases in 2017, a government spokesman said.

Since being introduced in 2008, more than 1,500 forced-marriage protection orders have also been issued, preventing people from being forced to wed and assisting in repatriating victims.

In the past decade, British diplomats, working in tandem with the unit, have rescued scores of women from forced marriages in Pakistan.

"We dealt with 59 cases in Pakistan last year, 10 male victims and 49 female," a spokesman for the British High Commission in Pakistan told CNN.

Last year, British diplomats assisted with 16 repatriations, through rescues or protection orders, he added.

The rescues are sometimes sensitive "snatch" operations, with diplomats secretly making contact with women living in forced marriages and then swooping on their houses to make rapid getaways with the victims in armored cars.