The start of the school year in Europe each autumn is a period when education resumes its place at the heart of the lives of pupils and their families. The equivalent of this annual cycle is very different in the central Asian state of Uzbekistan, where soon after their own school year begins, most students will be pulled out of classes to work in the cotton-fields for two months.

Andrew Stroehlein is media and information director at the International Crisis Group

Also by Andrew Stroehlein in openDemocracy:

"The war in American hearts and minds" (11 September 2006)

"A responsibility to protect: the world's view" (5 April 2007) - with Gareth Evans

"Medellín: revival and risk" (8 July 2008)This is not their choice or even a poverty-driven decision made by desperate families trying to make ends meet. This is a top-down government policy: the authorities close the classrooms, they put the children on buses, and they give them a police escort to the fields. Repeated regime pledges to end the practice have come to naught: even as the Uzbek government announced a ban on child-labour on 15 September 2008, children were already in the fields, picking cotton under compulsion.

The sheer scale of the annual operation is staggering. In this country of 28 million people, 2 million-2.5 million children are forced out of school to pick cotton every year, according to a new study by the School of Oriental and African Studies (SOAS) in London. The report tracked compulsory recruitment of children between grades five to nine (ages 10 to 15) and find they were employed on the cotton-fields for between fifty-one and sixty-three days without even weekend breaks. About the only Uzbek children who escape are those in the capital Tashkent, in Samarkand and a few other large cities. For everyone else, it is not learning but hard labour that awaits them each autumn.

Cotton is big in Uzbekistan. The country's number-one export nets the regime, which controls the only agencies licensed to ship it abroad, over $1 billion dollars annually. But the kids who do the work see very little benefit. Some forced child-labourers receive a tiny wage, but many children are never paid a penny for their cotton-picking. It is in a strict sense child slave-labour. The economics are such that adult agricultural workers cannot compete, and go to pick cotton in neighbouring countries.

The conditions for Uzbek children during those weeks and months areawful. By day, they swelter through burning hot hours in dry fields thathave been sprayed with pesticides. At night, they are crammed together in the most basic of shelters, with little or no access to clean water and decent sanitation.

Also in openDemocracy on politics and conflicts in Uzbekistan:

Malika Kenjaboeva, "Uzbekistan: Stalinism without state benefits" (29 November 2001)

Sabine Freizer, "Midnight in Tashkent" (1 April 2004)

Deniz Kandiyoti, "Andijan: prelude to a massacre" (20 May 2005)

Anora Mahmudova, "Uzbekistan's window of opportunity" (26 July 2005)

Marcus Bensmann, "Andijan, Germany and Europe" (13 May 2008)The environment suffers as much as the kids. Cotton is a thirsty crop, and excessive draining of the rivers for cotton production has led to the Aral Sea shrinking to just 15% of its former volume. Overuse of chemical fertilisers has also poisoned large tracts of farmland, making them unusable for decades to come.

But it is the forced child-labour that is most disturbing in the immediate term. Thanks to a number of groups raising awareness of this issue internationally, including the Coalition against Forced Child Labour in Uzbekistan and the Environmental Justice Foundation, a worldwide boycott of Uzbek cotton has been taking root. The list of clothing and retail companies signing up is impressive: C&A, Marks & Spencer, Tesco, Hennes & Mauritz, Debenhams, and Wal-Mart (ASDA).

This is exactly the kind of pressure needed if the Uzbek regime is ever going to put an end to this annual tragedy. The country's rulers do not seem to care much about outside opinion with regard to human rights. Uzbekistan has thousands of political prisoners. The United Nations special rapporteur on torture has said torture is "systematic" for those in custody of the security services. The regime thinks nothing of shooting hundreds of its own citizens dead in the streets when they try to protest, as it did in the eastern city of Andijan in May 2005, when perhaps 750 people were gunned down - followed by forced confessions and show trials as the state tried to cover up its guilt. In its own bleak way, the annual round-up of children for hard labour in the cotton-fields is preparing them for life in one of the most repressive regimes on earth.

International condemnation from all corners has not shamed the government of President Islam Karimov into halting or even slowing any of these other abuses. But cotton is money, so the regime cares.

Until the Uzbek government truly ends this annual abomination, the world is right to avoid the product of forced child-labour. It is time for Tashkent to hear the message, start paying adult workers a decent wage, and leave Uzbek children to get on with their schooling each autumn.