LONDON, England — PASSENGERS stepping out of London Bridge tube station cannot help but crane their necks to gaze at the jagged tower under construction: The Shard is the tallest building in the European Union and looks like a slice of glass balanced on the edge of the financial district.

When the tower opens next year, visitors to the observation deck will see helicopters fly by at eye level and take in the metropolis all the way to the distant north Downs Hills. The structure designed by renowned Italian architect Renzo Piano dwarfs nearby landmarks like Tower Bridge and St Paul’s Cathedral across the Thames.

The ambitious project speaks of now faded boom times: £1.5 billion ($2.34 billion) price tag, fancy restaurants, corporate office space, posh hotel. But it is being completed as Britain and Europe totter on the brink of recession — and the Shard will loom over a city in decline.

Neighbours are hoping the dramatic tower, visible from most parts of London, will bring big spenders to its south-of-the-river location, for centuries the less prosperous side of the Thames.

“I like the design, I like the promise. I think it’s going to blast this neighbourhood out of the water,” said Cherille McNeil-Halward, 71, who runs a picture framing shop a few minutes away from the Shard. “This tower will bring people with money to spend here, and that’s got to be a good thing.”

There is no question that the Shard is a riveting addition to the traditionally low-rise London skyline. But some complain it dominates the view, obscuring sights such as St Paul’s impressive dome.

The developer Irvine Sellar sees the project as a symbol of London’s status as a world city. The 72-floor, 310 metre- (1,016 foot-) tall building is designed by an Italian, financed by the Qatar government, and the Chinese hotel group Shangri-La were the first tenants to sign up.

“We want this building to be a building Londoners will feel ownership of,” said Sellar. “You can eat there, you can work there, you can sleep there. And you can see the view from there.”

The building’s exterior will be finished in June but it is unlikely to open until early next year. It will open in a truly historic neighbourhood, close to the Tower of London, Shakespeare’s Globe, and Borough Market.

In fact, the ultra-modern Shard sits at the edge of ancient London. The first Roman settlement Londinium was nearby on the banks of the Thames. Charles Dickens’ “Little Dorrit” was set in the streets behind the Shard.

The developers conceived the project more than 11 years ago when there was a financial appetite for building tall. But it generated almost immediate opposition from conservation groups who didn’t want the fabric of the city changed.

English Heritage and other groups complained that the design did not fit in with the surrounding architecture, but were overruled.

Prince Charles, who has waged a passionate campaign against modern architecture, wryly referred to the Shard as “an enormous salt cellar” shortly after it won planning permission but has not formally tried to block the project.

Last year UNESCO said it is reviewing the status of the Tower of London as a World Heritage Site, partly because of the way the Shard and

other buildings loom over

its courtyard.

The future of the building is still not secure. Along with Shangri-La, some restaurants have signed leases, Sellar said, but most of the office space has not yet been rented at a time when many London-based businesses are striving to reduce costs.

A report by Barclays Capital published this month finds a correlation between the construction of skyscrapers and financial crises, concluding that ambitious building projects often open just as the economy declines.

It cites the economic and oil crises of the early 1970s, which coincided with the completion of the World Trade Center towers in New York and the Sears Tower in Chicago. In Malaysia the building of the Petronas Towers coincided with the Asian economic crisis on 1997. And in Dubai the Burj Khalifa — the world’s tallest building — went up as the emirate almost went bust.