A ship loaded with 1,600 tonnes of rubbish set sail on Wednesday (August 5) to return the rotting cargo to Britain from Brazil, where it had been shipped falsely declared as plastic for recycling.
Eighty-nine containers packed with trash that includes dirty diapers, used syringes, food waste and computer parts were hoisted on to the freighter MSC Oriane in the early morning hours at Santos, South America's largest port.
The incident outraged many Brazilians and prompted President Luiz Inacio Lula da Silva to criticize Britain and developed nations for urging higher environmental standards while using developing nations as garbage dumps.
Brazilian environment minister Carlos Minc has said he would raise the issue with Britain's climate change minister, Ed Miliband, who is currently on an official visit to Brazil.
Criminal investigations are under way in Britain and Brazil to discover how the waste came to be shipped this year and last to Santos and another port further south.
Brazil has fined firms that imported or handled the waste.
Ana Alice Pereira, head of the Brazilian environment enforcement agency Ibama in Sao Paulo, said Britain would also be held accountable for the waste containers.
"The responsibility, all those involved in this episode have been indicted, but there is a full investigation behind the facts that is still taking place. But the British government is also responsible because this garbage was sent from there," she said.
According to Ibama, the importing firms said they had been expecting shipments of recyclable plastic. But even the company that alerted the authorities to the trash was fined because it had no license to recycle.
Brazilian law prohibits the import of household waste for any purpose, including recycling.
Retiree Herberto Gomes, a Santos resident, said there was no reason for Brazil to be treated as a third world country.
"I think this was a lack of respect with the Brazilian people. Just because we are an emerging country, they think we're not important, but we continue to receive everyone in our country with our arms wide open, without prejudice of race, religion or color. Why do they treat us like this," he said, questioning Britain's attitude.
British police arrested three men in late July but no formal charges have been brought against them and they have been released on bail after surrendering their passports.