It’s a city of nearly 8 million where Mayor Bloomberg owns a townhouse. Paul McCartney, Gwyneth Paltrow, and Madonna all own homes here, too. It competed to host the 2012 Olympic Games. Architects Daniel Libeskind, Norman Foster, and Richard Rogers are all working here or have recently completed buildings. Rupert Murdoch owns a big, conservative, tabloid newspaper here. The art scene is sizzling, real estate is super-pricey, and sushi-lovers can choose from at least two Nobu restaurants. The business world revolves around a big stock market and lots of new hedge funds.

The list of parallels between New York and London has always been long, but lately, with booming economies in both cities and trendy restaurants moving into old industrial neighborhoods, the two are looking more like mirror images.

Some say the two have more in common than any other international cities on the planet, making them both allies and, increasingly, competitors in the global economy.

In the past few years, both have been terrorist targets, competed for the 2012 Olympics (London won), and passed smoking bans for bars, pubs, and restaurants. London’s ban, which is modeled after New York’s, is scheduled to go into effect next year.

Academics, financial analysts, restaurateurs, art gallery owners, architects, and people who’ve lived in both cities say while London is still blatantly British in personality, its finance, restaurant, and art industries look more like New York’s now than they did five to 10 years ago.

The financial sector in London has seen a flurry of new hedge funds and leverage buyout firms investing in European companies and using the city, which offers Americans access to Europe with no language barrier, as a home base. Simultaneously, new restaurants and art galleries have sprouted in neighborhoods that have little or no industry any more — in the same way they have in places like TriBeCa here.

“London is by far the closest city to New York on almost every scale,” the deputy mayor for economic development in the Bloomberg administration, Daniel Doctoroff, said. “In terms of the number of people, the percentage of people who are foreign born. It’s arguable that there is no city that is more similar to New York than London anywhere.”

The cities are both in the midst of construction booms, with building permits for commercial and residential development breaking records. For those who thought looking for an apartment in New York was a blood sport, realtors in London say prices for “flats” have shot up 17% this year.

“Last year, everyone was convinced that the market was going to fall,” a broker at Hamptons International in the Islington section of London, Rowena Jones, said. “But then the bonuses started coming in, and people began thinking we’ve got to buy, buy.”

The architect Daniel Libeskind, who created the master plan for the World Trade Center site and who designed a building for London Metropolitan University, said that as both cities have construction crews transforming, or adding to, their skylines, they are aware of good architecture. Londoners, he said, are more concerned with preserving history with new building. New Yorkers are more willing to be bold.

He said the two-year-old “Gherkin Building” that Norman Foster designed in London, which looks like a giant glass pickle, has broken the image “of what London used to be.” Lord Foster’s addition to the Hearst Building on West 57th Street in Manhattan has a similar glass and grid exterior.

For London, beating out New York for the 2012 Olympics was a major triumph.With six years to prepare for the games, the city is planning more than $7 billion in development, including athletic venues, housing, and retail.

While some in New York have suggested “congestion pricing” in Manhattan to reduce traffic in Midtown during the week, London started using the system in 2003. That city charges drivers for bringing cars into the center of the town. The initiative, which was pushed by London’s mayor, Ken Livingstone, has drastically cut back on traffic.

Mr. Bloomberg has said the idea is not on the table here. Instead, he has proposed reinstating the commuter tax, which was repealed in 1999.

Shows regularly go back and forth between theater districts in London and New York. The latest swap was the “History Boys,” in New York for “Avenue Q” in London.The two were hugely successful in their original cities and are drawing big crowds in their new locations.

There has even been talk of the British department stores Harrods or Harvey Nichols opening up in the New York landmark Plaza Hotel, while the Financial Times this weekend reported that Barneys New York will open its first overseas store in West London. Virgin Megastores sells music in Times Square and Union Square in Manhattan and at Piccadilly and Kensington in London.

There are differences between the two cities. The director of the Rothermere American Institute at Oxford University, Paul Giles, said London does not have the same “service culture” that New York and America has. He said stores close early, and the city is more spread out than New York, making it more difficult to get around.

“You’ll go into either London and New York and you’ll find a Virgin Megastore and a you’ll find Starbucks, but I think on a deeper level London is still a microcosm of England,” he said. He said most international cities now look more like one another than the small towns that surround them.

But the similarities are growing, and hard to ignore.

The general manager for BBC America, Kathryn Mitchell, said more American talent agencies are scouting in Britain and elsewhere to find the next television hit like “The Office,” which prompted an American spinoff.

“We’ve got a lot in common — originally because you came from us,” she said.