Are rich Westerners who choose to spend their holidays on some of the world's most deprived city streets simply indulging in a form of voyeuristic "poverty porn", or might they be playing a role in reducing global inequalities?
The question of so-called slum tourism is being explored by Fabian Frenzel, lecturer in the political economy of organisation at the University of Leicester, who is leading a major research project into the issue.
Dr Frenzel said that his interest in the topic had partly been sparked when he attended the World Social Forum in Nairobi, Kenya, in 2007.
He recalled that the 20,000 activists and delegates at the forum had wanted to be out in the slums, working with the slum dwellers, despite participants from African countries warning them to be careful about what they were doing. "I was also sceptical," he said. "There's an urge to relate to slum dwellers, but does it help relieve poverty?"
The first major conference on the theme, Destination Slum, was held at Bristol Business School in 2010. Now, Dr Frenzel, Ko Koens and Malte Steinbrink - who were also involved in the conference - have collected some of the papers in a book titled Slum Tourism: Poverty, Power and Ethics (2012).
Although they trace the phenomenon to the Victorian "slummers" who visited the poverty-stricken East End of London, the current trend was started by politically active travellers in the townships of South Africa and the favelas of Brazil. It has now spread to "garbage tours" in Mexico, visits to Buenos Aires taking in a transvestite brothel, tours inspired by Bob Marley in Jamaica and even, much to the irritation of the Indian authorities, tours of Mumbai inspired by the film Slumdog Millionaire.
Dr Frenzel said that one particularly ironic knock-on effect of the trend in Brazil was a sort of gentrification in the favelas.
"Areas which are poor and dangerous are particularly attractive to tourists, but the money they bring in tends to undermine their attractions," he said.
To take his research further and to contribute to wider debates about the impact of tourism on poverty relief, Dr Frenzel has now secured a Marie Curie Fellowship from the European Union.
While based at the University of Potsdam for two years, he will carry out fieldwork in Mumbai, Nairobi, Rio de Janeiro and probably both Cape Town and Johannesburg, interviewing residents, facilitators, tour operators and tourists.
"Victorians going into the East End", he noted, "had a very limited direct economic impact, but they made a long-term difference by changing attitudes to welfare and society."
Dr Frenzel's research should illuminate whether today's slum tourists could do the same.