"I would work each day for 16 hours. Then at 1am I would sweep the floor and sleep on the spot at my work station."

From the age of six, the boy was imprisoned in an illegal garment factory in Delhi, driven to exhaustion by a factory owner who kept him in conditions comparable to slavery, paying him 50 rupees - about 67 pence - per week.

Shivshankar is one of many thousands of Indian children internally trafficked from their homes each year and sold into bonded labour.  Most are recruited from uneducated farming families in the country's poorest rural states.

He explains: "When I was six years old a trafficker came to my village and persuaded my parents to send me away with him. He said he would give me a good education, as well as work.

"I came home from the fields one day and my parents said, 'Go with this man'. That day we went on a 12-hour journey. I was scared.  I felt so hungry on the train but was given only water.

"When we got to the factory it was huge. There were about 65 children and 15 adults. The bigger children used to beat me up and bully me.

"I was doing embroidery work on garments.  If I made even a slight mistake they would shout abusive words and beat me. I used to work from 9 am until one in the morning.

"One day I asked the owner about taking a few hours rest because I was not keeping well. He refused, even though I was ill and very weak. "

In India, it is illegal for children under the age of 14 to work, but the law is rarely enforced. When the local police visited the factory, they accepted bribes from the owner to turn a blind eye.

Shivshankar explains: "I missed my family but I was not allowed outside of the factory. It was like being in jail. They wouldn't even let me make a phone call."

In 2008, Shivshankar was rescued by local child labour activists Bachpan Bachao Andolan (BBA).

Now aged 13 and reunited with his parents, he is attending a BBA residential school and looking forward to a better future.

"When I was in the factory I couldn't play, or even run. I had no bat or ball. 

"Now at last I am free to play. I have played cricket for the first time. I had never seen computers in my life and now I know how to use them."

"When I am older I want to be a policeman. I won't receive any bribes, and I will help people."

Prohibition of child labour is one of the principles of the ETI Base Code. 

In the event that child labour is found to be present in the supply chain of a member company, that company is expected to work with their supplier to provide for the child's transition into sustainable, quality education.

But child labour is often hidden out of sight, away from principal factories and pack-houses, and the gazes of buyers or auditors. ETI works with companies to help them become more effective at monitoring conditions further down the supply chain, where child labour is more likely to occur.