On a sunny Sunday morning in Regents Park, people stroll along, and families with young children happily head for the zoo. Walking in the opposite direction is a uniformed policeman, carrying a machine gun. The face of London has changed.
London is defiant but different. Sirens are everywhere. It is normal for the city but these days the noise is continual and they are not just patrol cars, they are vans filled with officers dealing with the hoaxes and security alerts.
Over the weekend railway stations were closed as bomb hoaxes were checked out. On Saturday Euston was closed twice for a couple of hours. Yesterday there was a security alert at King's Cross, the scene of the greatest atrocity, and Whitehall was cordoned off for more than an hour after a scare.
Londoners ignored sirens before, now they watch where the police vans are heading, worried that they might be signifying another terror attack.
Still they carry on and everybody is smiling and talking. A city which is labelled impersonal has suddenly come together, a sorrow shared and a willingness to resume normal life in the face of threats.
But there are the constant reminders - when they sit in traffic on the Euston Road behind a No 30 bus or venture on to a tube train, it is not so easy. On the way to Paddington Station, police stand at cordoned-off areas at every road leading to Edgware Road underground.
The scene is similar at all the bomb sites.
Police tear around every part of London and there are suddenly bobbies in their distinctive helmets on the beat in Park Lane.
At the permanent concrete security barriers, such as the roads leading to the Grosvenor Square home to the US embassy, there are now police personnel manning the barricades.
There are police at every railway station and they patrol the Heathrow Express trains. More patrol the platforms.
Heathrow has stepped up its security. Passengers heading for the Irish Republic will now see police officers at checkpoints beyond the normal security checks.
Spot checks on hand luggage and body scans are being carried out at departure gates.
For now London life has changed, whether it can ever return to normal again is anybody's guess.