The annual peace service at Westminster Cathedral acquired fresh significance on the evening of 9 August 2011, as Londoners gathered to pray for their city and other English communities torn by rioting.
A fourth night of unrest had brought total arrests in London to more than 700, according to police, and looting and arson continued to spread to other cities in Britain.
The authorities believe that a huge police operation and bad weather helped prevent a fifth night of trouble.
One man has been reported killed and dozens of citizens and police officers have been injured, authorities said.
The rioting began on 6 August after a peaceful demonstration in north London over the police killing of a 29-year-old man, Mark Duggan.
One attendee among the 200 people at the Roman Catholic peace service said she needed a feeling of hope.
"Faith gives hope that current fears and insecurities will pass and we will feel safe on the streets again and trust our young people," said Ellen Teague, a freelance Catholic journalist who writes regularly for The Tablet, JUSTICE magazine, Independent Catholic News, Redemptorist Publications, the Messenger of St. Anthony, EniNews and Ekklesia.
Meanwhile, the Catholic Archbishop of Westminster, Vincent Nichols, issued a statement declaring: “The scenes of the last few nights in parts of London and elsewhere are shocking. The criminal violence and theft that have been witnessed are to be condemned. They are a callous disregard for the common good of our society and show how easily basic principles of respect and honesty are cast aside.
“I ask that Catholics pray especially for those directly affected by the violence, for those facing danger on the streets, for those whose livelihood has been ruined, for those whose lives are marked by fear, for those whose parents are worried about the behaviour of their youngsters and for those who, at this time, are being tempted into the ways of violence and theft.
“In the face of these difficulties, a forthright common effort is needed to ensure that these times bring out the best in our society and not the worst. I am sure that, as Catholic citizens, we shall play our part with clear principles for living, both as individuals and as a society, with honesty, compassion and prayer.
“May God grant us courage and determination to shape our lives with dignity, self respect and care for the common good,” Nichols concluded.
The Archbishop's press office said that he "will not be giving any interviews in connection with this statement".
EniNews (www.eni.ch) contributed to this report