LONDON -- The small and ancient heart of London was transformed yesterday into a citadel on the Thames in defense against the Irish Republican Army.
The precise square mile known as the City, which comprises today's financial district and was the site of the Roman settlement from which London grew, was virtually closed off to nonlocal traffic.
Checkpoints were established on eight streets entering the area, and access through nearly 20 others blocked.
Scanning cameras were mounted here and there throughout this neighborhood of banks and brokerages interspersed with sandwich shops, ancient pubs and tailors dealing almost exclusively in pin stripe suits.
Sniffer dogs sensitive to the scent of explosives were deployed.
Cars, trucks, any suspicious vehicles are liable to search. Police will occasionally go armed. Buses and taxis will be permitted to enter the borough through only one street, Moorsgate. The other seven will be for private cars and service vehicles.
These measures could be in force for at least a year, or maybe longer, if the Parliament approves extending them.
All these, and perhaps some provisions not made public, comprise the response of the Corporation of the City of London to the clandestine bombers of the IRA.
Michael Cassidy, the chairman of the corporation, said the measures "would cause minimum inconvenience." A spokesman for NatWest Bank, the most recent victim of the IRA's bombers, said, "We support any action to prevent a third bomb attack."
Over the past 15 months, IRA bombers have made London's financial nerve center their preferred target. The evidence of their last attack, on April 24, is prominent on the skyline.
Soaring office blocks in Bishopsgate -- the NatWest Tower and adjacent high rises -- stand without windows, without employees, their insides recently cleared of rubble. Edifices all around are cracked and in many cases unusable.
That blast, a truck bomb, killed one man and injured 36 other people.
A year earlier, on April 10, 1992, a 1,000-pound car bomb took out the Baltic Exchange Building. That blast killed three people and injured 91.
Total losses from the most recent bombing were estimated at $1.6 billion in property and lost trade.
The City is an optimum target for the IRA for a number of reasons. It is one of the world's top three financial centers, and the after-effects of bombings there are visible evidence of the IRA's ability to strike on the British mainland.
Few people live there. Most of the 300,000 or so people work in banking and finance, and those who service those industries go home in the evening, leaving only a few thousand residents. So IRA bombs can do maximum property damage with limited loss of life.
Not everyone thinks the closing of London's core borough is the best idea. Andrew Pharaoh, director of Movement for London, a lobby that campaigns for improved roads and traffic control in the country, predicted "traffic chaos."
He is concerned that vehicles that used the City as a through route will now be thrown onto alternative roads that might not be able to handle them.
Gwyneth Deakins, a councilor in Tower Hamlets, an adjoining borough to the City, said: "It's an act of incredible arrogance. . . . the City corporation is acting as if it was on a planet of its own and not in central London."
Nor is the government pleased. A home office representative was quoted as saying: "If you impose severe and draconian measures, you are playing into the hands of the terrorists. It is important that commercial life of the City is not brought to a stop. You must never let the terrorists win."
'Lives would be shattered'
But Owen Kelly, the commissioner of the City of London Police, countered that another large bomb would be an even greater IRA propaganda coup. "If we do nothing, how would we explain the inaction to the bereaved and those who would be terribly injured and whose lives would be shattered?" he said.
"Then you have to think of the perhaps irreparable economic damage that would be done to the City and its reputation as a safe place to do business."
"The city institutions wish to be better protected," said Tony Travers, the head of the Greater London Group, an academic metro research unit at the London School of Economics. "They want to make certain that international financial institutions are not put off coming to London."
The Corporation of the City of London is a self-governing, elected authority, much like local authorities that govern other parts of London. But it is different in a number of ways.
For one thing, it has a lot more money than the others, deriving largely from grants left to it over the past 700 to 800 years by businesspeople and successful merchants.
It has its own police force, the only one in the country whose coat of arms does not include the royal crest or any reference to the monarch.
This exception, Mr. Travers said, "reflects the traditional hostility between the city and the government . . . [and] its historical inclination to separate itself from politics . . . in order to free itself to concentrate on money and commerce."
This sense of independence, according to Mr. Travers, does characterize the City and accounts for its continuance through so many centuries.
"The square mile is an organization that has managed to survive several hundreds of years against all external threats. Threats from the monarch, from the Luftwaffe [which almost annihilated the neighborhood during the Battle of Britain] and from competing financial centers," said Mr. Travers.
"If I were asked which of the three medieval institutions in England would survive -- the monarchy, the House of Lords or the Corporation of the City of London -- I would certainly wager that the City will outlive the other two."