Iain Banks, the author, joined veteran Labour politician Tony Benn, Respect MP George Galloway, Bashir Mann, convener of the Muslim Council of Scotland and human rights lawyer Gareth Pierce, among others, to appeal to the courts to stop pursuing Mr Anwar.
Mr Anwar is facing a contempt of court charge for speaking out against a series of verdicts in September. His client, Mohammed Atif Siddique, had been jailed for eight years on terrorism offences and Mr Anwar reacted by issuing a strong press statement outside the court.
Mr Anwar claimed that the verdicts were a tragedy for justice and freedom of speech and alleged that his client had not received a fair trial.
Lord Carloway looked into Mr Anwar's remarks and decided that the lawyer had made an "unjustified attack on almost every area of the trial process".
The judge then passed the issue to the courts to decide whether Mr Anwar had been guilty of contempt of court.
If Mr Anwar is found to have been in contempt of court, he could be jailed - a prospect which has angered many senior politicians and lawyers.
Last night, a number of high-profile Scots came together in Mr Anwar's defence and sent a letter to The Scotsman warning the courts could cause considerable damage to freedom of speech in Scotland if the case against Mr Anwar was pursued.
The authors of the letter stated: "The possibility that Aamer Anwar may have to face contempt charges is deeply worrying and is an unprecedented attack on freedom of speech."
The letter writers praised Mr Anwar's work as a human rights lawyer over the last few years and added: "If the judiciary is successful in silencing Aamer Anwar, then this will have far-reaching consequences.
"We should all be very worried if the effect of this case is to make lawyers reluctant to carry out this work for fear of the repercussions.
"We believe that the current attack on Aamer Anwar is an attack on the fundamental right of all lawyers to represent their clients."
Last night, Mr Anwar said he could not comment while the issue was still "under judicial consideration".
However, in a further development which will increase the pressure on the judiciary over the case, Margo MacDonald, the independent MSP, said that she wanted to raise the issue in the Scottish Parliament, probably in the form of a parliamentary motion, if she was allowed to do so.
Ms MacDonald said: "I am concerned about any restraint being put on lawyers who speak their minds, give their opinions or campaign against injustice - and Aamer Anwar does all three.
"When he spoke after the guilty verdict against Mr Siddique, he was speaking on behalf of his client and I think it might have been wise for everyone to take account of the heightened sensitivity at that time."