MORE than 3000 people have added their support to an open joint letter backing a former diplomat and his ally who have been charged in connection with the Alex Salmond case.

Well-known figures including Pink Floyd musician Roger Waters, linguist Noam Chomsky and playwright Sir David Hare wrote to the Lord Advocate about the decision to charge Craig Murray and Mark Hirst in relations to comments they made about the case. Both Murray and Hirst deny the charges.

The "Friends of Mark Hirst" Twitter account says the new support has been gathered in just 24 hours.

READ MORE: Global figures including Pink Floyd star sign letter backing Craig Murray

The open letter to James Wolffe QC was also signed by former Greek finance minister Yanis Varoufakis, human rights campaigner and author Tariq Ali and Kristinn Hrafnsson, the investigative journalist and editor in chief of Wikileaks.

“In recent weeks vocal independence supporters and backers of the former First Minister Alex Salmond, specifically the former UK diplomat, human rights campaigner and journalist Craig Murray along with fellow journalist Mark Hirst, have been arrested and charged in relation to comments they made publicly during and following the trial of Mr Salmond,” the letter said.

“Whilst we appreciate that you cannot be involved in individual cases you will undoubtedly be aware that complaints of alleged contempt of court were made against six other individual journalists widely regarded as being hostile in their reporting of Mr Salmond.

“No action by the Crown Office or Police Scotland has been taken against any of those individuals. This leaves the distinct impression that Police Scotland, at the direction of the Crown Office, are acting in a manner that is both biased and disproportionate.”

Salmond was acquitted at the High Court in Edinburgh in March of all 13 sexual offence charges brought against him by nine women in a two-week trial.