The Duke and Duchess of Cambridge and Prince Harry attended a 'Service of Hope' for those caught up in the murderous attack by Khalid Masood in London two weeks ago.
Masood, 52, was himself shot dead after he ran down pedestrians on Westminster Bridge, killing three people and injuring dozens more, and then stabbed PC Keith Palmer to death at the Palace of Westminster.
Although it was quickly billed as a terror attack by police and claimed by Islamic State, no evidence of terrorist links have emerged in investigations and Masood appears to have been acting alone and possibly become radicalised through material he accessed on the inernet.
In the bidding, the opening prayer, at Westminster Abbey, the Dean of Westminster John Hall said: 'The violent assault two weeks ago against Londoners and visitors to this city from around the world and the killing of a police constable on duty at the Palace of Westminster have shocked people everywhere.
'Today we remember in particular those who lost their lives: Aysha Frade, Kurt Cochran, Leslie Rhodes, Keith Palmer, their families and friends, and all those who were injured. We commend them to the care and keeping of almighty God.
'We give thanks for the vigilance and dedication of the Police and Security Services and we pray for them in their vital work of keeping our communities and nations safe from terror and random violence.
'We pray today for the communities of our United Kingdom, so rich in their diversity, that we may all celebrate what each contributes and that we may live in harmony.
'At a time of sorrow, a time when we are tempted to despair, may we find hope.'
In his sermon, he added: 'Those killed and injured included Londoners but also people from the United States of America, from Romania, France, South Korea, Italy, China, Australia, Greece, Portugal, Germany, Poland and Ireland.'
He asked could possibly motivate a man to hire a car and take it from Birmingham to Brighton to London and then drive it fast at people he had never met, couldn't possible know, against who he had no personal grudge, and then run at the gates of the Palace of Westminster to cause another death.
'It seems likely that we shall never know. What on earth did he hope to achieve?'
Those present included Home Secretary Amber Rudd who read from Jeremiah 31: 'Thus says the Lord: A voice is heard in Ramah, lamentation and bitter weeping. Rachel is weeping for her children; she refuses to be comforted for her children, because they are no more. Thus says the Lord: Keep your voice from weeping, and your eyes from tears; for there is a reward for your work, says the Lord: they shall come back from the land of the enemy; there is hope for your future, says the Lord: your children shall come back to their own country.'
Prince William read the parable of the Good Samaritan from St Luke: 'A man was going down from Jerusalem to Jericho, and fell into the hands of robbers, who stripped him, beat him, and went away, leaving him half dead.
'Now by chance a priest was going down that road; and when he saw him, he passed by on the other side. So likewise a Levite, when he came to the place and saw him, passed by on the other side.
'But a Samaritan while travelling came near him; and when he saw him, he was moved with pity. He went to him and bandaged his wounds, having poured oil and wine on them. Then he put him on his own animal, brought him to an inn, and took care of him. The next day he took out two denarii, gave them to the innkeeper, and said, "Take care of him; and when I come back, I will repay you whatever more you spend." Which of these three, do you think, was a neighbour to the man who fell into the hands of the robbers?' He said, 'The one who showed him mercy.' Jesus said to him, 'Go and do likewise.'
London Mayor Sadiq Khan read the prayer of St Francis:
'Lord, make us channels of your peace. Where there is hatred let us bring your love. Where there is injury, your pardon, Lord. Where there is doubt, faith.
'Make us channels of your peace. Where there is despair in life, let us bring hope. Where there is darkness, only light.
And where there is sadness, ever joy.'
