More than 900 academics have urged the UK government to reverse its decision to prevent climate scholar Andreas Malm from entering the country, warning that it threatens academic freedom and freedom of expression. The open letter says scholars must be able to travel, exchange ideas and take part in debate, including on politically contentious subjects.

Malm, an associate professor at Lund University in Sweden and author of How to Blow Up a Pipeline, was stopped from entering the UK last week after the Home Office said his presence might not be conducive to the public good. His electronic travel authorisation had been revoked, and Malm said he had not been told the reasons.

He had been scheduled to attend an academic conference, appear on the BBC and join a public discussion organised by Tribune with Huda Ammori, a co-founder of Palestine Action, which is proscribed in the UK. Malm said he suspected the planned discussion was behind the decision.

The letter warns that excluding academics because of their political views or the subjects they discuss could set a dangerous precedent and discourage open academic and public debate. It has gathered more than 1,400 signatures from people at over 250 academic institutions, according to the account. Fabian Dablander, the London School of Economics assistant professor who initiated it, said the response reflected deep concern in the academic community.

A Home Office spokesperson said an ETA may be cancelled or refused for various reasons, including concerns that someone poses a public-safety threat or seeks to spread extremism. The spokesperson added that this is not a ban on entering the UK: people in this position can apply for a visa, allowing their circumstances and suitability to be considered further.

Sources: The Guardian Education.