Victims of the Islamic State terror group and other injustices around the world have been remembered in a peaceful demonstration in London.
Mike Haines, 51, who has campaigned for peace since his humanitarian worker brother David was beheaded by IS, told the largely Muslim crowd: "It is important that we react in a positive way against these hate-mongers. "
The event was organised by Muslim groups to mark the religious festival of Ashura.
It is a time which carries key messages about the importance of justice, freedom and the idea there should be no justification of wrongdoing in the name of religion.
Mr Haines spoke of how his younger brother was held captive for 18 months, beaten and tortured along with other hostages before being murdered on September 13 2014.
His family's trauma was deepened when his death was filmed and posted on the internet.
Struggling to hold back tears at times, particularly because it was so close to the anniversary of his brother's death, Mr Haines said: "I mourn my brother every day.
"However he knew the risks of being a humanitarian worker.
"He and my family accepted those risks because he was doing important work, helping his fellow man regardless of creed, colour, race or religion."
The retired mental health nurse from Dundee condemned the "truly disgusting atrocities" carried out by IS and others against innocent people.
He said: "The callous murder of my brother, the bombing of a teenage concert in Manchester, the deplorable attack on a place of worship in Finsbury Park, the inexcusable name-calling of people based on their religion or colour - they all have one thing in common which is to incite hatred."
He said hatred "steals the humanity from a person" and society must not allow this destruction to win.
Mr Haines added: "It is only by working together that we can combat the hatred of the extremists.
"It starts on a very basic level as individuals and then pervades upwards through the strata of our society."
Thousands of Muslims turned out for the demonstration which started at Hyde Park and worked its way through central London. People of all ages, including families and children, were among those who took part, with some holding banners which read "Muslims condemn terrorism" and "180K imams have spoken against IS".
Some finished the demonstration with prayers at a mosque, while others headed to Trafalgar Square.
Mustafa Field, of Faiths Forum For London, said: "I think that it is important that we are seen to be talking about this.
"Muslims and imams across the country have condemned this threat.
"We are pushing back against this evil ideology."
Catriona Robertson, director of the Christian Muslim Forum, said: "Today is an important day and this is an important procession.
"It is something that people from many different backgrounds can learn from."
Against the backdrop of world suffering, she described it as a time that people of different beliefs who are "aware of our own histories and traditions can come together with integrity" to try to work for a "just and compassionate society".
By Helen William
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