Climate change sceptics have been emboldened to press their case in the countdown to the Copenhagen talks after seizing on a clutch of e-mails sent to and from climate change experts appearing to show them plotting to manipulate data and hurling abuse at their sceptical peers.

The exchanges, purported to have been written by British and US scientists at the UK's University of East Anglia, debate data and whether it should be released and include abusive language aimed at climate change sceptics.

One e-mail from Phil Jones at UEA to several climate scientists spoke of using a “trick” to hide “the decline” of temperatures. It is not clear from the context what he means exactly but sceptics said it showed that scientists were concealing temperature data that appeared to run contrary to the idea of global warming.