Prime Minister David Cameron and Britain's most senior police officer were among the guests at a memorial service for murdered teenager Stephen Lawrence.
The 18-year-old died when he was attacked by a gang of racists as he waited for a bus in Eltham, south east London on April 22 1993.
Twenty years to the day since his death, his mother Doreen was joined by friends, relatives and supporters of the charitable trust that she set up in her son's name at St Martin-in-the-Fields church near Trafalgar Square in central London.
She told the congregation: "I've always tried to look forward and to focus on the positive since Stephen's murder, and looked to see how I can make the lives of others better. The pain of losing someone never goes away, you just learn to live with it at cost.
"Over the years as a family we have mourned in our separate ways, not daring to speak out loud about our feelings. My pain is raw, and that of my children."
A number of senior political figures including Deputy Prime Minister Nick Clegg, Labour leader Ed Miliband and Home Secretary Theresa May also attended.
The first candle at the service was lit by Mrs Lawrence and her surviving son Stuart and dedicated to building hope in memory of Stephen.
Mr Cameron read Our Last Awakening by John Donne, while Mr Miliband and Mrs May gave readings from the Bible. There was also an address by Dr Richard Chartres, the Bishop of London, who said he would have liked to have known Stephen. The music spanned traditional hymns, through to Gospel and a powerful rendition of Fallen Soldier by singer Beverley Knight who has performed the same song, especially written for Stephen Lawrence, at previous memorials.
Mayor of London Boris Johnson told the congregation: "On a dark street in Eltham 20 years ago there took place a crime that caused shock and pain, and disbelief, and outrage. And it was left to those who had suffered the greatest pain and loss, the family of Stephen Lawrence, to search for the truth and for justice."
But he said that the success of the Olympics had shown the best of the diversity of London, adding: "The world was watching us, and they saw that incorrigible happiness and that unity in diversity. And what people prophesied five decades ago would be a defect and difficulty in our society has been alchemised into the genius and magic of London."