Tiyamike Phiri is 14, with the long skinny legs of a girl entering adolescence. In another world, she would be with friends in the school playground. Instead, she is bent double at the hips, gouging out weeds from the earth under a savage sun between banked rows of tobacco plants using a heavy hoe, made of a tree branch and a metal plate.

She looks up in some wonderment, unused to questioning such a life for a child. She is not unusual. There are 18 tenant families on this tobacco farm in the Kasungu district of Malawi, each living in a straw hut. Only two of the other girls go to school, she says. Two-year-old Jackson Phiri stumbles past. He has a miniature hoe, fashioned by his father, Lazaro, because he cried every time he saw his mother and father set off for the fields carrying tools and wanted one for himself. There seems an inevitability about the lives of these children.

“I left school last year because I had no school materials,” said Tiyamike, her eyes on the ground and her voice quiet. “I liked school. I liked Chichewe [her language] best. I got very good grades. But my main problem was I had no exercise books and nothing to write with.”

Without a pen and an exercise book, she could not do schoolwork, her teachers pointed out. But she lives with her older brother and his wife and baby and they have nothing. “I help them in the fields,” she said.

She would go back if she could. “I would like to do nursing,” she said. Instead, she weeds, builds earth banks for the tobacco plants and sews the harvested leaves together to suspend them from branches so they dry in the air. Weeding is the worst. “It is a hard job,” she said.

Tiyamike is just one of many children in Malawi who see little future beyond the tobacco fields.

A report in 2011 estimated there were 1.3 million worldwide under the age of 14. The figures are hard to come by, but the International Labour Organization last year reported that child labour was on the increase, in spite of the tobacco companies’ protestations that they are working to end it. “Child labour is rampant,” the report said.

Research conducted in Malawi revealed that 57% of all children in two tobacco producing districts were involved in child labour; among tobacco growing families, 63% of children were engaged in child labour.

Dreams of escape

These children live in the poorest of families. Tiyamike’s brother Madalitso Phiri, 27, took her in seven years ago after their father died. He doesn’t want her or the rest of his family to work in the tobacco fields. Like many of the tenant farmers, he sees tobacco as a cash crop that will give him a windfall at harvest time, with which he can change their lives. “I need to get capital so I can buy land and stand on my own two feet and my children can be brought up well,” he said. “I want my children to own shops and sell things.”

It’s a dream the tenant farmers all nurture. That when the money comes in, they can go back to their home villages and buy land to farm for themselves or open businesses. But when the crop is sold, the money is never enough.

No safety net

Yeriko Phiri, 26, and his wife, Esther Banda, 20, thought their son, three-year-old Chifundo, had malaria. They took him to hospital, with a promise from their landlord that he would pay the bill.

Eight days later, Yeriko was still working alone in the fields. He and his neighbours were very worried – without Esther’s help, he would not be able to get all the work done. In the end, Esther offered to leave her pots and plates, which she had been using to prepare food for herself and her son, with the hospital as surety. Then she set off on the 9km walk home, with Chifundo on her back.

When she arrived home, the family were together again, but not smiling. “We haven’t had lunch today. We don’t have money to go to the mill to grind maize.”

The families are given a weekly ration of maize, which they grind to a flour, mix with water and eat twice a day as a porridge. They are given salt and the tools they need, but have no cash unless they do extra piecework in the maize fields.

Because he was alone, Yeriko could not do the piecework after working on the tobacco plot to afford the 300 kwacha (40 cents or 30p) to mill a pail of maize.

The 17 tenant families – 18 including the farm manager – started the season in October and will work on the land for about 10 months until the crop is sold and they get their money.

Tobacco growing is hard labour and poorly recompensed. Chimkukuzi Dickson, a tenant farmer who is also farm manager and earns 200,000 kwacha ($277, £209) a year on top of what he gets for his crop, finds it hard to recruit new workers. Farms poach from each other. “On some estates there may be problems. I tell [the workers] at my farm: you get enough food and you get some cash.”

“Lots of people think that way. Others have nothing to eat [so they will agree to work in the tobacco fields]. They have no alternative.”

The leaf buyers

The leaf-buying companies, Alliance One, Universal – in Malawi known as Limbe Leaf – and the tobacco giant Japan Tobacco International (JTI), which does its own buying, grade the tobacco and decide the prices farmers are paid. The leaf buying firms say they tell contract farmers not to use children and that stopping child labour is a priority.

In Malawi, the bales are transported by lorry to the auction halls in the capital, Lilongwe – a cost paid by the farmers. Most farmers are under contract to a leaf buyer. If they don’t take the price they are offered, they could put their bales up for auction but they risk not selling at all.

Studies of the livelihoods of farmers in five low-income countries led by the economic and health policy research programme of the American Cancer Society in Atlanta, Georgia, have found that farmers at the end of a season just repay debts. “Unequivocally for the vast preponderance of these leaseholders, the livelihood is very bad,” said Jeffrey Drope, the programme’s vice-president.

Drope said that families “admitted to pulling their kids out of school to work in handling tobacco directly without protection”. The children were exposed to wet leaves – with the danger of contracting green tobacco sickness – as well as fertilisers and pesticide, he said. The companies insist under-18s are only permitted to work with dry tobacco and that they have training policies to minimise risks with green tobacco

“Handling dried tobacco is not considered as hazardous work,” JTI said.

BAT says "education is key" on safe practices​ with green tobacco​; PMI's prevention advice includes wearing long sleeves, gloves or rainwear.

A study in Malawi, headed by Donald Makoka of the Centre for Agricultural Research and Development in Lilongwe, found even the earnings of the contract and independent farmers who sublet to tenants were inadequate.

It noted: “In 2011, two of the largest European tobacco firms, British American Tobacco (BAT) and Imperial Tobacco, had profit margins of 34% and 39% respectively. By implication, the high profit margins of the tobacco transnationals are in part a function of the impoverishing unpaid labour of tobacco farmers’ households.”

'My friends, this is the world'

For the tenant farmers, whose cheap labour substantially contributes to the profits made by the companies, it’s a grinding life of hard labour seven days a week. But it is only human to try to alleviate stress from time to time.

In the farm the Guardian visited in Kasungu, Isaac Mboba, 20, has made a guitar from an old vegetable oil canister and a piece of wood. “My aim was to become a musician … I never saw a guitar but I thought I could create my own musical instrument. I saw pictures in the newspapers.”

Mboba sings as the children dance. “My friends, this is the world / Take care of it / People are not good / The whole world has problems / Help us, hold our hands / We are poor / Don’t leave us alone.”

How are the companies taking action?

The tobacco industry says it is opposed to exploitative child labour.

All the major companies contribute to the Eliminating Child Labour in Tobacco (ECLT) Foundation, set up in 2000, including Philip Morris International (PMI), BAT and JTI, as well as the leaf buyers Alliance One and Universal. The International Labour Organization, the only UN agency to have dealings and take funds for projects from the industry, is an adviser to the board. Because it is independent, the companies say, the foundation can require governments to take action.

The ECLT Foundation says it has removed over 182,000 children from tobacco farms since 2011 in Kyrgyzstan, Malawi, Mozambique, Tanzania and Uganda, and sent 27,000 to school and vocational training. That amounts to less than 15% of the reported total number of child labourers. The foundation also works in Indonesia and Guatemala.

The companies say they have made it clear to farmers that they must not use child labour. PMI established a programme in 2011 “to improve labor practices and progressively eliminate child labor on all farms from which we purchase tobacco”. There is monitoring and countrywide assessments of labour practices and “engagement with stakeholders” for improvement.

PMI funds the NGO Verité, which works towards “supply chain sustainability”, to evaluate the effectiveness of the programme, it says on its website.

BAT says: “We have always made it clear to all our suppliers of tobacco leaf and contracted farmers that exploitative child labour and other human rights abuses will not be tolerated.”

About 1% of its tobacco is bought from Malawi, all of it through leaf buyers such as Alliance One. The relationships are governed by the industry’s Sustainable Tobacco Programme (STP), run by AB Sustain, which is part of the agricultural division of Associated British Foods.

“The ... [programme] requires that all farmers are compliant with ILO child labour standards and that all farmers receive training on child labour prevention,” said BAT in a statement.

BAT says it commissioned a report from a development consultancy called DD International in 2012 which found tobacco farmers were not trapped in poverty but were increasing in prosperity. The report looked at 40 or so case studies in three countries – Brazil, Bangladesh and Uganda.

BAT and JTI consider it acceptable for children of between 13 and 15 years of age to do light work on a family farm, provided it is light work permitted by local law. JTI quotes the ILO, which says: “Work that does not affect their health and/or personal development, or interfere with their education, can generally be regarded as positive.”

JTI says all its suppliers are assessed via the Sustainable Tobacco Programme. The company has a scheme called Arise (Achieving Reduction of Child Labor in Support of Education), which it says has taken more than 39,000 children out of child labor in Malawi, Brazil, Zambia and Tanzania since 2011.

Alliance One says the elimination of child labour is a “top priority”. It purchases most of its tobacco from contracted farmers whom it can direct to comply with policies including “a prohibition against employing anyone under the age of 18 for hazardous tasks”. It seeks compliance through education and training and has more than 700 people in Malawi working on “agronomic and labor standards” with farmers. It also has a commitment to improving farmers’ incomes, it says.

Universal says it takes “the issue of child labor very seriously” and is undertaking “significant efforts around the world to mitigate the risk of child labor in our supply chain”.