The e-mail system of one of the world's leading climate research units has been breached by hackers, with e-mails between scientists released on the internet.
Research from the University of East Anglia's Climatic Research Unit played a key role in the Intergovernmental Panel on Climate Change's Fourth Assessment Report.
Some climate change sceptics say the hacked material is proof that scientists have conspired to overstate the human influence on climate change.
But the university says the e-mails have been taken out of context and cannot be used to discuss the issue responsibly.
The break-in comes two weeks before the United Nations climate change conference in Denmark.