A group of international academics has condemned a United Nations convention which bans child labour as “harmful and unnecessary”, arguing that allowing young children to work can have positive effects which are not being taken into account.

In a controversial letter to the Observer, the researchers, who all work in the fields of child development or human rights, say the UN committee on the rights of the child has ignored available evidence in favour of outdated and ill-informed western prejudices and policies which can have a negative impact on the ground.

Across the globe, 193 countries have committed to ending child labour by 2025 under the UN’s sustainable development goals. But the academics want the existing minimum age (15 in some countries, 18 in others), to be abandoned, arguing that “age-appropriate” work can be beneficial for children in both the developing and the developed worlds and gives poor children a chance to improve their lives.

One of the signatories, Dr Dorte Thorsen of the school of global studies at the University of Sussex, said: “Banning children from work doesn’t bring them back into school; in fact, it might do the opposite if they were working to pay their school fees.

“For some children it’s a matter of rational economics. We have years of evidence that show that work doesn’t end a childhood and often can enhance it, can create a solidarity. In some countries in Africa, and in India, we are seeing collectivisation movements of child workers, a unionisation where they are trying to participate in politics, be heard, as opposed to this being a story of victimisation and oppression.”

Thorsen criticised the Department for International Development minister Priti Patel for pressuring British companies to scrutinise their supply chains for evidence of child labour, a task Thorsen says they are unlikely to have the competence to perform properly.

The experts also pointed to the setting up of schools in some countries for employees, which had then closed after pressure from the international campaign against child labour. Other children, they said, have been forced into hazardous, dangerous or illegal work because more regulated employment became closed to them.

Richard Carothers, a Toronto-based child development expert at the International Child Protection Network, said: “The hard-headed attitude of the big bureaucratic international agencies, immediately putting kids out of work because they think they should be playing football instead, is definitely not the way to approach this. Children need to be protected from nasty situations, and there is a debate about whether the percentage of working children in nasty situations is a small percentage or a very small percentage, but in no way does fixating on an age limit help kids in situations where they are being harmed.”

He said that UN officials should listen to children’s views. “How do they want things changed for them? How do we change things for working children? We need to be developing far more nuanced policy, more sophisticated understanding. Once a country ratifies a UN convention, then this translates into national law, and that’s it. Too simplistic. It’s damaging. We have case study after case study where children and their families have been damaged.”

Mélanie Jacquemin, a sociologist from the University of Marseille, is now in the Côte d’Ivoire, researching stories of children and adults who have migrated from village to city as children to find work. She said the stereotypes of exploited children were the exception.

“Yes, some child workers are in harsh situations. They are not matching the standards we have for decent work at all, they can be exploited and sometimes they are overworked. And of course if someone has your passport and you are deprived of your liberty and in a slavery situation, then this is a very important issue – trafficking does exist.

“But all the studies have shown that, although important morally, these cases are very much a minority issue compared with the great majority of children who are working under decent conditions, particularly here in west Africa.”

Young workers need help to avoid pitfalls, she said, and children, whether in Africa or Europe, will sometimes go and expose themselves to risk and be exploited. But banning work represented a grave error by big international agencies, she said, and was a decision based on “extremes of experiences that don’t cover the experiences of real people living and learning”.

The UN committee on the rights of the child did not respond to requests for comment.