The Met Office has embarked on an urgent exercise to bolster the reputation of climate-change science after the furore over stolen e-mails.

More than 1,700 scientists have agreed to sign a statementdefending the "professional integrity" of global warming research. They were responding to a round-robin request from the Met Office, which has spent four days collecting signatures. The initiative is a sign of how worried it is that e-mails stolen from the University of East Anglia are fuelling scepticism about man-made global warming at a critical moment in talks on carbon emissions.

One scientist said that he felt under pressure to sign the circular or risk losing work. The Met Office admitted that many of the signatories did not work on climate change.

John Hirst, the Met Office chief executive, and Julia Slingo, its chief scientist, wrote to 70 colleagues on Sunday asking them to sign "to defend our profession against this unprecedented attack to discredit us and the science of climate change". They asked them to forward the petition to colleagues to generate support "for a simple statement that we . . . have the utmost confidence in the science base that underpins the evidence for global warming".

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Met Office reports on temperature changes draw on the work of the University of East Anglia's Climatic Research Unit, from which the e-mails were hacked. Phil Jones, unit director, has agreed to stand down while an investigation takes place into claims that he manipulated data to exaggerate the warming trend and tried to block publication of alternative views.

One scientist told The Times he felt under pressure to sign. "The Met Office is a major employer of scientists and has long had a policy of only appointing and working with those who subscribe to their views on man-made global warming," he said.

Professor Slingo denied that the Met Office had put anyone under pressure. "The response has been absolutely spontaneous. As a scientist you sign things you agree with, not because you are worried about what the Met Office might think of you," she said.

The 1,700 signatories, a fraction of the research scientists working in Britain, include Sir John Houghton, former chairman of the science working group of the Intergovernmental Panel on Climate Change, Sir Brian Hoskins, head of the Grantham Institute at Imperial College, and Professor Lord Hunt of Chesterton, a climate scientist at University College London.

Professor Slingo said the statement was carefully worded to avoid claiming all climate scientists were beyond reproach. It says the evidence for man-made global warming is "deep and extensive" and comes from "decades of painstaking and meticulous research by many thousands of scientists across the world who adhere to the highest levels of professional integrity".

Benny Peiser, of the Global Warming Policy Foundation, which claims man-made climate change has been exaggerated, said the petition showed that the Met Office was rattled.