Colin Parry lost his 11-year-old son, Tim, in the bombing.
Following the tragedy he founded the Warrington Peace Centre to encourage better understanding between young people from different backgrounds.
He was among the guest speakers at Rebuil
ding Hope After The Bombings, a conference organised by the Chartered Institute of Public Relations. It was inspired by Robert Webb, a local authority public relations officer whose sister, Laura, was among the 52 people killed by the terrorists in London on July 7.
A month-long exhibition, focusing on the themes of the conference at the Thackray Medical Museum, opened today at the Art of Propaganda Gallery in Wakefield.
Mr Webb said: "Laura's death was a huge blow to us all. Five months on, we are still coming to terms with her loss. But Laura was a positive person, so the best way that we can honour her memory is to face the future with optimism.
"We can't bring Laura back, but if we can help prevent such a loss from happening again, then we are living up to the example she showed us all."
Among the other speakers were broadcaster and journalist Darcus Howe, whose Channel 4 series White Tribe examined the essence of "Britishness"; Tuehl Miah, of Joseph Priestley College, who was describing how the Beeston community responded to July 7 and Coun Stuart Bruce (Lab, Middleton Park), a public relations professional.
Leeds Metropolitan University is to produce a report on the insights and lessons generated by the conference.
Profits raised from the event which runs from 9.30pm to 4pm will be donated to the Tim Parry Jonathan Ball Trust and to families of victims of the London bombings.
