LONDON — Mayor Bloomberg is making the case that New Yorkers need to get used to the idea of being watched. Security cameras are capturing their every move, he said this morning.

“I do think that in this day and age, if you think that cameras aren’t watching you, you are very naïve,” Mr. Bloomberg said during an appearance at London’s riverfront City Hall with the city’s mayor, Ken Livingstone.

Mr. Bloomberg went on to say that “we are under surveillance all the time.” “The people of London, I think not only support it, if Ken Livingstone didn’t do it, they would try to ride him out of town on a rail,” he said. “We live in a dangerous world and people want to have security cameras.

Mr. Bloomberg was in town to talk with Mr. Livingstone about London’s congestion pricing scheme, a version of which he is trying to implement in New York, and to see London’s so-called Ring of Steel, a web of security cameras that monitors all traffic in the center of the city.

During a tour of the surveillance control room in a London police precinct, Mr. Bloomberg said the city is “way behind” when it comes to municipal cameras on subways and buses. The MTA “just has to get us this kind of technology,” he said.

The executive director of the New York Civil Liberties Union, Donna Lieberman, said that while the NYCLU is not opposed to such technology, government has an obligation to ensure that safeguards are put in place. City Hall has failed to expose its surveillance programs to “sunlight,” she said.

She added: “If you can’t walk for three blocks in Manhattan without it being captured on camera then we have to worry about being turned into a Big Brother society or whether we’re a free society that we all cherish.”