Ms Hall, 28, and Mr Pears were among the last of 35 people to die at the hands of gunman Martin Bryant in what became known as the Port Arthur Massacre. Another 23 people were wounded. Dr Leigh went on to become a professor of economics at the Australian National University before being elected as the Labor member for Fraser, in the ACT, in 2010. He never forgot the tragedy that had claimed the life of his mentor. While a professor, he teamed up with statistician Christine Neill to investigate whether the Howard Government’s tough gun laws and the mass buyback of guns from Australian citizens - which followed the massacre and which received bipartisan support from the Labor Opposition led by Kim Beazley - had saved lives. Among the conclusions Leigh and Neill reached was that the measures had saved an extraordinary 200 lives every year by averted homicides and more particularly, suicides.

On Wednesday, Leigh and Liberal MP John Alexander will launch the Parliamentary Friends of Gun Control. It will be precisely 21 years since the buyback of about 661,000 guns was completed in 1997. Mr Alexander, a former champion international tennis player who holds John Howard's old seat of Bennelong, has his own reasons for supporting gun control. Loading He lived for 14 years in the United States, a nation plagued by shooting deaths.

One evening, while hosting a dinner party at his home in Atlanta, Georgia, one of his friends told him: “John, you've got to get a gun”. “It turned out that I didn't know one person there who didn't own a gun," he told Fairfax Media. He couldn’t imagine why people living in urban areas needed to own guns. Among the guests at Wednesday’s ceremony to launch the Parliamentary Friends of Gun Control will be Walter Mikac, the man who became the public face of the agony caused by the Port Arthur massacre. Mr Mikac lost his wife, Nanette, and their two children, Alannah, 6, and Madeline, 3, to Martin Bryant’s shooting rampage.

Dr Leigh says he will never forget the words of Mr Mikac when he subsequently addressed a crowd of 3000 people in Sydney's Domain: “As you know, three months ago to this day, I lost the entire reason for my existence.” Mr Mikac went on to establish The Alannah and Madeline Foundation, dedicated to keeping children safe from violence, and he was a leading advocate of Australia’s gun laws. Also attending Wednesday’s ceremony will be former deputy prime minister and Nationals leader Tim Fischer. Former deputy prime minister Tim Fischer is supporting the initiative. Fischer put his political career on the line by travelling country Australia in the months after the Port Arthur Massacre, backing Howard’s insistence on tough gun laws at rallies attended by hugely unimpressed rural gun owners.