Probe into leak of climate change emails is closed

A two-and-a-half year investigation into the embarrassing leak of hundreds of emails apparently designed to cast doubt on the scientific case behind climate change has been shut down without the culprit being found, police said last night.

The leaked data, from the Climate Research Centre at the University of East Anglia, was revealed just before an important 2009 climate conference in Copenhagen and were seized on by sceptics who claimed they showed that scientists colluded to manipulate data.

The Government's former chief scientist told The Independent in 2010 that he suspected that a foreign intelligence agency was behind the leak. Norfolk Police said last night that the operation was a "sophisticated and carefully orchestrated attack" but said that it had been unable to identify who was behind it.

Detective Chief Superintendent Julian Gregory said: "The complex nature of this investigation means that we do not have a realistic prospect of identifying the offender or offenders and launching criminal proceedings within the time constraints imposed by law."