Young girls who work on vast tea plantations in India are being tricked into lives of slavery and sexual abuse by traffickers.

Earning less than £1 a day, the children, some as young as 11, are promised better jobs as domestic servants in cities, where they are then sold into slavery.

Parents will even sell their children to traffickers, with the promise that money will then be sent home.

It is believed that thousands of girls have been trafficked in what has been dubbed the "Tea Maids Trade".

In Delhi alone, it is believed that 100,000 young people are in domestic slavery.

Now a mission is underway to track down children from tea plantations who have gone missing, and are feared to have been sold into slavery.

So far, 20 children and teenagers have been rescued, with tea producer Tetley confirming that some had been trafficked from the vast Nahorani plantation in the Assam province, part-owned by Tetley's parent firm Tata Global Beverages and the World Bank's investment arm.

Somila Tanti was 16 when she was trafficked, and was held in domestic slavery for three years before recently being rescued and reunited with her family.

"I was told 'come with us and you will earn good money'. We were poor. I thought it would be good," she told the Sunday Mirror.

Her first owner was a doctor, who did not mistreat her, but would not allow her to go home. After 11 months she was moved to a new owner.

"I was abused badly at the second place," she said. "This man was very bad. He used to touch me in my private parts and try to rape me."

In her entire time as a slave, she said she was forced to sleep on a floor with no bedding.

"I cried and I missed my parents – but I had a deep feeling in my heart that one day my father would come to search for me," she said.

In a documentary by Guardian Films, Somila is shown being reunited with her parents. Before her rescue, she was hours away from being sold into prostitution.

Anti-slavery campaigners say that the traffickers are able to lure youngsters owing to the pitifully low wages plantations pay, with tea pickers in Assam paid just 94 rupees, 91 pence, a day. The legal minimum wage in Assam is 169 rupees a day.

Kailash Satyarthi, founder of the Bachpan Bachao Andolan child rescue movement, criticised the tea companies for raking in vast profits, while traffickers were allowed to operate with impunity.

He said: "The owners of these international tea estates don't care for these people. Forget decent wages, they don't pay survival wages."

"The reality is endless slavery. The reality is abuse."

Tetley insisted that tea picked on the Naharoni estate does not end up on the British market.

In a statement, its parent company said: "Tata Global Beverages is committed to the fair and ethical treatment of people across our supply chain and we take their welfare seriously."