Recently, Mohammed Atif Siddique was sentenced to a total of eight years for terrorism offences. Irrespective of the differing views on the outcome of the case, the criticism levelled at Mr Siddique's solicitor, Aamer Anwar, over a statement that he released on the day of the verdict is extremely disturbing.

Following sentencing on October 23, Aamer Anwar was ordered to appear at a court hearing before the judge. He was accused of showing disrespect to the judge, the jury and the court. Aamer has now been informed that the matter may be remitted to another High Court judge to consider contempt of court proceedings against him.

The possibility that Aamer Anwar may have to face contempt charges is deeply worrying and is an unprecedented attack on freedom of speech. Aamer has earned a reputation as one of the most prominent human rights lawyers in Scotland today. He represented the Chokhar family in their long struggle for justice and has diligently defended asylum-seekers. He has represented victims of the "war on terror" who were accused of terrorism and who were eventually proved innocent of the charges laid against them. In 2005, he helped campaigners negotiate a way to the G8 summit at Gleneagles and defended demonstrators arrested during the protests.

Following the collapse of the World's End Trial, the Lord Advocate stressed the importance of the independence of the judiciary and prosecution. Equally as important is an independent defence, which is often all that stands between the accused and the state. We might not always agree with Aamer Anwar, but he is part of a rich and important tradition of campaigning lawyers that speaks without "fear or favour".

If the judiciary is successful in silencing Aamer Anwar, then this will have far-reaching consequences. A lawyer's job is to represent their clients to the best of their ability - no matter what crimes they are accused of. All those who campaign against injustice and for a better world know that one day they may have to face the state in a courtroom. They need lawyers who are willing to advocate and speak out on their behalf. 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 the current attack on Aamer Anwar is an attack on the fundamental right of all lawyers to represent their clients.

Tony Benn, president, Stop the War Coalition; Moazzam Begg, ex-Guantanamo Bay detainee; Iain Banks, author; George Galloway MP; Lindsey German, national convener, Stop the War Coalition; Professor Mike Gonzales, University of Glasgow; Imran Khan, human rights lawyer; Bashir Mann, convener, Muslim Council of Scotland; Professor David Miller, University of Strathclyde; Gareth Pierce, human rights lawyer; Mohammed Sarwar MP; Sandra White MSP; and many others.

Lord Carloway appears to be confused about the role of defence lawyers in the legal system, complaining that law agents should not attack the courts or the law. Defending Mohammed Asif Siddique, it was Aamer Anwar's duty to represent his client, not to act as an ambassador for the court or Parliament.

Aamer Anwar has maintained that he was, indeed, espousing the thoughts of his client. Yet even if they were his own beliefs, the notion that lawyers are not at liberty to set forth their opinions should offend everyone who believes in freedom of speech.

Should we next expect to see Baroness Helena Kennedy QC tried for her continuing eloquent and lucid criticism of anti-terror laws?

Geraint Bevan, 3e Grovepark Gardens, Glasgow.