In the past four months, three rationalist and humanist bloggers have been hacked to death by Islamist gangs on the streets of Bangladesh. Avijit Roy was one of those three. Roy was attacked by a gang of Islamists wielding machetes; al-Qaeda in the Indian Subcontinent has recently claimed responsibility for the brutal attack, and Islamist fundamentalists are systematically working their way through a “hitlist” of writers and free speech advocates published online.

On the streets of Bangladesh, Islamist extremists aiming to suppress free speech operate in a culture of impunity; the police stand idly by, whilst the government has in the past seen fit to imprison not the perpetrators, but the victims of these brutal attacks.

Roy’s widow Bonya Ahmed, who was attacked alongside her husband, but survived, is now visiting the United Kingdom to deliver the Voltaire Lecture, making her first public appearance since Roy’s murder. Although shaken by his death, Bonya has sworn to continue the struggle against censorship and violence. She recognises her husband’s murder as an act of terror, as "a crime not only against a person, but against freedom of speech and humanity", and she is determined that those behind the attack do not succeed.

On 2 July in central London, Ahmed will speak out about her continuing battle for free expression, in her first public appearance since the attack. We hope to have our own presence at the event, and encourage all members to consider this opportunity to show our solidarity with the Bangladeshi rationalist writers who face death every day.

The extreme challenges to freedom of expression we all know of are not diminishing; they are increasing. It is important now more than even that we remain vigilant and demonstrate our solidarity with those who have given so much in defence of free expression.

For full details about the event, and to get your own ticket, please visit the British Humanist Association website.