After facing criticism for its apparent failure to launch an investigation into the illegal dumping of UK computers in Africa, the Environment Agency has revealed that a formal investigation into the firms believed to be involved in the practice is taking place.

A spokeswoman for the Agency said an investigation was underway following a Greenpeace report this summer which found PCs from a number of UK local councils and universities, including Kent County Council, Southampton County Council and Salford University, had been illegally exported to Nigeria and Ghana, where they were being broken up in conditions hazardous to the workers involved.

She was unable to confirm which companies are being investigated or when the investigation first started, but insisted that it had been underway since the summer and rejected any suggestion that it had been launched as a result of criticism of the Agency.

The Agency had faced condemnation from green groups after it initially responded to inquiries in late August from BusinessGreen.com's sister title Computing by claiming it required more evidence before it could launch a formal investigation.

In a statement released at the time, a spokeswoman for the Agency said it did not have the jurisdiction to investigate waste that had already left the country.

"If we thought that there may be evidence held abroad that relates to an investigation of offences in England or Wales (or both) in the form of witnesses and forensic evidence that are vital to us bringing a case to court, we would consider securing that evidence, but only through the correct legal channels," she said. "We could not just go and collect witness statements abroad without reference to our own and the foreign country's criminal justice system."

The Environment Agency's initial response appeared to differ from that of some of the universities and councils caught up in the scandal.

Kent County Council and Salford University said they would immediately be contacting their waste contractors to find out how the machines had ended up in Ghana, while chairman of the Local Government Association (LGA) Environment Board, Paul Bettison, said he would write to the Environment Agency and urge it to take more action to tackle the problem.

However, the Environment Agency now insists it did move swiftly to investigate the issue and is continuing with its inquiries. "It is now a case of watch this space," said the spokeswoman.

The news was welcomed by IT re-use charity Computer Aid International, which late last month launched a campaign, backed by a petition on the Downing Street web site, calling on the government to provide extra funding to support the Environment Agency's efforts to tackle the illegal shipping of electronic waste to Africa and Asia.

"The government has a key role to play in policing eWaste and Computer Aid would welcome any action from the Environment Agency that will help to prevent the UK's eWaste being shipped to the developing world," said Louise Richards chief executive of the charity, which refurbishes IT equipment in the UK and distributes it to social projects in the developing world.

"Fraudulent commercial traders in the UK are actively abusing re-use and recycling initiatives and the illegal export and dumping of hazardous waste in countries like China, Ghana and Nigeria must be stopped," she added.