PROVIDENCE, R.I. — Every Olympics in recent memory has opened with an aerial shot of a new stadium set in the glamorous host city. Come the 2012 London games, a very big mosque may take up much of the stadium’s environs.

How big a mosque? A 16-acre complex able to hold 70,000 people. America’s largest mega-church, Lakewood Church in Houston, seats only 25,000. Britain’s largest cathedral, in Liverpool, accommodates a mere 3,000. If built, the London Markaz would become the biggest place of worship in Europe.

As you can imagine, many in Britain feel highly conflicted over the proposed mosque for its size and location — and we haven’t mentioned its sponsors. The concerns range from the creation of a Muslim city within London to questions about national identity. Letting this mega-mosque go forward would be a big mistake.

The social dimensions of the giant complex could rival the physical ones. Britons worry that their growing Muslim population is splitting from the larger society and becoming radicalized. Prime Minister Tony Blair recently called the Islamic veil a “sign of separation, adding, “That’s why it makes other people from outside the community feel uncomfortable.”

The concern is not over a new mosque. London has more mosques than any other Western city. It’s the magnitude. The mosque would take over the Borough of Newham, creating a self-contained Muslim world within London. Muslims are already moving into the area in anticipation of changes to come.

Only two subway stops away in Leytonstone, British Home Secretary John Reid was recently urging Muslim parents to keep their children away from extremists, only to be told to leave the neighborhood by a well-known local firebrand. Abu Izzadeen shouted down Reid, saying, “How dare you come to a Muslim area,” after the authorities had arrested suspected militants.

Izzadeen has earned fame for describing the London subway bombers as “completely praiseworthy” and longing for the day that all Britons submit to Sharia law. Izzadeen is a publicity hound — the son of Jamaican immigrants, his given name was Trevor Brooks — and mainstream Muslim groups routinely denounce him. But he’s has gotten a ton of press, including a full-court interview on BBC.

A conservative Islamic missionary group called Tablighi Jamaat would build the London Markaz. (Saudi Arabia is expected to pay for much of it.) U.S. antiterror officials believe that extremists have been infiltrating this generally peaceful organization. “American Taliban” John Walker Lindh had ties to it. “If al-Qaida needed a fresh set of bodies in order to pull an operation,” Steve Denny, a former FBI agent who followed the group, told NBC, “one of the places that they would go for that fresh set of bodies would be Tablighi Jamaat, whether it’s in the United States or not.”

Then there is the issue of British identity. Whether the majority population goes to church or not — and they don’t go much in Britain — the cultural roots remain Christian and Western. Many fear the mega-mosque would eclipse London’s iconic Christian landmarks, St. Paul’s Cathedral and Westminster Abbey. It’s a coincidence, but a noted one, that the Kingsway International Christian Centre, Europe’s biggest evangelical church (seating capacity 12,000), is being torn down to make room for the Olympic stadium.

The project still awaits final permits, but the London Development Agency has already expressed interest in having this Islamic landmark in the city.

So it’s likely that come the 2012 London Olympics, the world’s sports fans will be sitting in their loungers and wondering where the heck London went. By then, however, a mega-mosque may more accurately represent what the city of Big Ben has become.