Anthony Berry MP was among five people who died when the IRA explosion ripped through the Grand Hotel on October 12, 1984.
His daughter Jo Berry now travels the world promoting peace and reconciliation with Patrick Magee, the republican bomber who planted the deadly device.
“I would say he is a friend,” she said. “It is an unusual friendship but I care about him.”
Thirty people were injured in the attack on the eve of the Conservative Party conference but the main target, prime minister Margaret Thatcher escaped relatively unscathed.
Although reluctant to say she has forgiven Magee for causing her father’s death, Ms Berry claimed she understood why he turned to violence three decades ago.
She added: “I don’t like to use the word (forgiveness). For me it is more about empathy and understanding. And the empathy is about understanding from his perspective why he did it.
“I am always going to be against any violence but if I understand why he, and others, chose to use violence then that can help me to look at how we can make the world a place where people are less likely to use violence.
“Forgiveness is such a difficult word. But he is my friend now. We spend a lot of time together.”
At the time of the bombing, Ms Berry, now a mother in her 50s, was a 27-year-old meditation student who had sympathised with the IRA hunger strikers’ pursuit for political status in the Maze prison.
She was about to jet off to Africa when the harrowing news of the bomb filtered through.
“It was a massive shock and we had a long, long wait before we eventually got the news in the afternoon that they had found my dad’s body and that my step mother was injured,” she said.
“I didn’t just lose my father in that bomb — someone I had become really close to — I lost a part of me and I felt very strongly that I was now part of the conflict in Northern Ireland.”
Magee was handed eight life sentences in 1986 but was released under the terms of the Good Friday Agreement in 1999, having served just 13 years.
A year later, Ms Berry, who had deliberately stayed away from the court proceedings and distanced herself from the media coverage of the event, met him at a friend’s house in Dublin.
She did not tell her siblings about the clandestine meeting which marked the beginning of a “miraculous” journey.
“It started with him giving me some political rhetoric which I had heard before,” she added. “It was very much ‘we’ talking rather than ‘I’. He was talking for the group — for the IRA, or for Sinn Féin — rather than himself. But, I was very curious about what was beneath that.
“I didn’t go into the meeting wanting to argue with him or prove points. It was really to listen and understand.
“He was disarmed by my giving him empathy and there was a second part of the conversation where he had taken off his political hat and was speaking much more as a human being.”
Ms Berry, who now runs the Building Bridges for Peace charity, decided within two days of her father’s death to extract something positive from the tragedy.
Although she never imagined that it would involve meeting and eventually forging a friendship with the man responsible for her grief.
The reconciliation talks have taken her and Magee to places like Palestine, the Balkans, Rwanda and Colombia.
Ms Berry believes her father would have approved of her actions.
She said: “I hope he would have understood and given me his support. I think he would have. I am not a politician but, in my own way I think he’d understand that I am trying to change things.
“I never thought I would be planning two events in Brighton on the 30th anniversary with Patrick Magee.
The pair will be taking part in a panel discussion at The Old Market in Hove to mark the 30th anniversary of the explosion.
Ms Berry said it was important Magee attended.
She said: “For me, inviting Pat to be there on Sunday is to show a living example of reconciliation and the power of empathy. It is really important to have him there to demonstrate that.
“Yes, some people will be upset but, I think, that for peace sometimes you have to take these risks.”
Magee has declined to give press interviews ahead of the 30th anniversary of the bombing.