Helping out at an African nursery or digging trenches in rural India might have become a fashionable – and expensive - rite of passage for thousands of young people each year, but volunteers would often do more good staying at home and assisting communities on their own doorstep, a conference on ethical tourism will hear tomorrow.

The growing trend for far-flung gap years often combining an element of work in a developing country has become one of the fastest-growing phenomena in the global travel industry.

However, a leading UK charity is warning that whilst often well intentioned in their motives, altruistic young travellers can end up doing more harm than good to their host communities, even potentially fuelling child abuse.

Mounting concern that the desire to work in orphanages in countries such as Cambodia and Nepal is actually be leading to the abandonment or even abduction of children from their parents to fuel the boom in eager tourists has led to calls for a radical rethink on the ethics of so-called volunteerism.

Delegates at a one-day conference at Braithwaite Hall in Croydon, south London, organised by Tourism Concern will seek to persuade prospective volunteers to think hard about their choice of destination.

The charity’s executive director Mark Watson said that whilst the desire to help others was commendable – too many expensive commercial volunteering opportunities ended up exploiting both those offering help whilst harming the lives of those meant to be on the receiving end.

“Volunteers often have unfulfilling and disappointing experiences; volunteer placements can prevent local workers from getting much-needed jobs; hard-pressed institutions waste time looking after them and money upgrading facilities; and abused or abandoned children form emotional attachments to the visitors, who increase their trauma by disappearing back home after a few weeks,” Mr Watson said.

“We feel that there are many opportunities for people to undertake meaningful volunteering in their own community, where they will receive proper training, support and supervision – without the need to pay a tour operator for the privilege. In the majority of cases people would be far better (and have a more rewarding experience) volunteering at home and spending their money on travelling and staying in places listed in our Ethical Travel Guide,” he added.

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Among the speakers at the event is campaigner Philippa Biddle, who described taking part in a development project building an orphanage and library in Tanzania. She said each night local men dismantled the structurally unsound work they had done – relaying bricks and resetting timbers whilst the students slept.

“Basically, we failed at the sole purpose of our being there. It would have been more cost effective, stimulative of the local economy, and efficient for the orphanage to take our money and hire locals to do the work, but there we were trying to build straight walls without a level,” she recalled.

Laura Woodward of Raleigh International, a non-profit making sustainable development charity which works with young volunteers and communities around the world living in poverty, said few commercial organisations offered high quality placements that brought benefit to their host countries.

She said the conference was right to highlight concerns over voluntourism.