The community of Ealing in west London was slowly returning to normal yesterday as detectives searching for last week's bombers were completing a forensic examination of the site of the explosion.
Several police cordons close to last Thursday's bombing, thought to have been carried out by the "Real IRA", have been removed and police are confident many people evacuated after the 40 kg bomb exploded will be allowed to return to their homes this week.
The RUC Chief Constable, Sir Ronnie Flanagan, said he had "suspicions" about who was responsible for the bombing and had no doubt they would be arrested.
He told BBC's Breakfast with Frost programme that with public co-operation police would track down the bombers.
Sir Ronnie added: "They are a very real threat and if you plotted their terrorist capability against the growth curve of, for example, the growth curve of the Provisional IRA and their capability you would find these people are quite a distance along that curve."
Detectives believe two "Real IRA" cells are operating in Britain. They are examining CCTV footage from cameras on the M40 in the belief that the Ealing bombers may have travelled to London from the Oxford area, according to reports at the weekend.
It is also understood police are examining a fingerprint found on a discarded bus ticket near the scene of the car bomb that exploded outside BBC headquarters in west London in March, an attack which was widely believed to be the work of the "Real IRA".
Scotland Yard said the ticket was "of interest" and police believe the fingerprint could belong to a suspected dissident republican terrorist.
Meanwhile, about 100 people attended a morning Mass at Christ the Saviour Catholic church close to the bomb blast to pray for those injured in the explosion.
Two people remain in hospital and Father Peter Needham said the service allowed people to express their feelings about the bombers. "We should ask for forgiveness for the terrorists," he said.
"They don't want to hear that. They expect people to say they hate them and they should be banished to the deep blue sea but that is what they expect. The way to deal with this is through forgiveness."
One of those attending the Mass, Mr William McCarthy, originally from Dublin, added: "It is disgraceful. People are shocked. It has to stop, there is no need for it."
Up to 50 people who were evacuated from their homes and those who have been unable to get to their premises since the blast are expected to return to the area within the next few days. Initial excavation work has revealed that none of the buildings close to explosion needs to be demolished.
However, a structural assessment of Ealing Broadway will have to be carried out before the busy route will be fully reopened to traffic.
Michael Bradley in Belfast writes:
On BBC television, Sir Ronnie Flanagan said paramilitary organisations exploited the freedoms afforded by liberal democracies. "Therefore that is why it is of crucial importance that the public at large continually work in partnership with us," he said.
"So yes, we have our suspicions, yes I have no doubt we will bring to justice those people, but to continually engage in that sort of success we need full public co-operation and understanding.
"It is only in that atmosphere of co-operation that we can really bring to an end the activity that these people seek to engage in."
Sir Ronnie rejected claims that gardai had been more effective in combating the "Real IRA" than the RUC.
"It's not true. We have had a whole range of successes, as have our colleagues in the Garda Siochana.
"Together we have brought a whole range of success against these people but occasionally they do succeed.
"Now that is no comfort whatsoever to the victims of incidents when they do succeed," Sir Ronnie added.
The Chief Constable warned against underestimating the threat posed by dissident republicans.