In the immediate aftermath of the 7/7 bombings, many adjectives were used to describe London's response: stoical, determined, calm. "We're not afraid" became a rallying cry.
But in the wake of last week's copycat attacks and the fatal shooting by police of an innocent man on the subway, the mood has palpably shifted from unyielding to uneasy. For a city that has weathered Nazi air raids and Irish Republican Army bombings in the 1970s, it's hardly a time of total panic. But some here wonder whether the terrorists are starting to achieve their desired effect.
Though Britons are adamant that terrorists will not alter their way of life, some things are clearly changing. Subway traffic, for instance, is down about 15 percent, transit officials say. The armed police presence is noticeably higher. There are more bicycles on the roads.
And those still sanguine enough to ride the subway report a very different mood. Some say the lesson from Israel about suicide bombers is to be vigilant for shifty, sweaty individuals mumbling to themselves. Most people on the Tube now fit that category.
"There is a sense of unease, people checking each other out, looking at bags that sort of thing," he adds.
"Things have definitely changed," says Matthew Thacker, a publisher who was evacuated from the subway on Thursday during the copycat attack in which three Tube trains were targeted by explosive devices that failed to detonate properly.
British police indicated that they have established a tentative link between the London suicide bombers and the men behind this latest attack. The connection involves a whitewater rafting trip in Wales attended by two of the suicide bombers shortly before their attack.
Tube drivers are also unnerved. Some union officials have warned that drivers may be reluctant to operate trains if attacks continue. But while Thursday's failed attack frightened many, Friday's incident left Londoners astonished. Police chased a terror suspect into a train, pinned him down in front of dozens of people, and shot him repeatedly in the head.
Although such events are exceedingly rare in Britain, Sir John Stevens, a former police chief, said tactics have been revised recently to deal with suicide attacks.
It turned out that the man was no bomber, just a young Brazilian electrician named Jean de Menezes. Police had tracked him for several miles from what they say was a suspicious address. When he ran from police into the subway, officers felt they had to act. Police officials have expressed regret over the "tragedy," but have defended the shooting.
The recent incidents appear to be putting people off traveling into central London. Retailers reported a very quiet weekend (apart from bicycle salesmen), and said that sales had fallen by a quarter.
"The most fundamental question we must now ask is whether shoppers will no longer consider the July 7 attacks as a one-off event but as part of an ongoing threat," said Tim Denison of the retail data firm SPSL.
Tourism officials also fear a dearth of visitors, though they say tourists will flock back if the attacks stop. "We anticipate an initial drop-off in bookings, but it will have recovered by year end," says Elliott Frisby of the VisitBritain tourism authority.