Europe An Island No More Hello! Allo!

By CHRISTOPHER REDMAN PARIS

As the sea gull flies, the distance is not great: 21 miles from Cape Gris- Nez in France to the famous white chalk cliffs of Dover on the English side. Yet down the centuries the narrow neck of water separating Britain and France has served as one of Europe's most enduring physical and psychological barriers. Only twice have armies crossed it to invade Britain: the Roman legions in 54 B.C. and the one led by William, Duke of Normandy, in 1066. Secure on their sceptered isle, Britons developed their own proud brand of insularity, summed up as "splendid isolation" during the palmy Victorian era.

A century later, despite Britain's belated entry into the European Community in 1973, the effects of the country's psychological detachment were still on display last week when Prime Minister Margaret Thatcher's go-it-alone refusal to join the rest of the European Community in plans for political and monetary union prompted the resignation of Deputy Prime Minister Sir Geoffrey Howe. Ignoring his gentle nudgings toward greater European cooperation, Thatcher declared, "In my view, we have surrendered enough."

But the days of isolation mentality are numbered. Last week Britain ceased % to be an island for the first time since the end of the last Ice Age, when meltwater covered the land bridge joining the British Isles to the mainland. On Oct. 30 a team of workers at the face of the French section of the service tunnel that is being bored 131 ft. below the bed of the Channel waited for a thin steel probe, drilled from the British side, to pierce the wall of chalk marl in front of them. The 2-in.-diameter aperture opened by the probe could not be seen at first, but then the British crew sent a blast of compressed air through the hole, blowing out the last crumbs of marl.

The probe breakthrough confirmed that French and British tunnelers were within striking distance of completing the first tunnel under the English Channel. Measurements taken through the probe hole showed the two approaches were out of line by a horizontal distance of only 20 in. after huge boring machines had chewed their way through 24 miles of undersea chalk. Said a spokesman for TransManche Link, the Anglo-French consortium responsible for design and construction: "It was like throwing out a line to the moon and getting within a 10-ft. circle." The remaining 325 or so feet of chalk separating the two tunnels will now be excavated, and on Dec. 1, nearly three years after digging began, a large enough gallery will have been shaped to enable men from the two sides to meet.

After some rocky debates over responsibility for cost overruns, the international consortium of banks that provided the bulk of the financing for the project has agreed to put up an extra $6 billion to complete the project, which will have a total cost of $14.7 billion. In addition, $1 billion will be raised this month from a share offering.

The breakthrough confirmed that Britain is destined to become a more integral part of the Continent. The tunnel, commonly called the Chunnel, is scheduled to be completed in the summer of 1993, in time to benefit from the 12-nation European Community's plans to dismantle all internal barriers to the movement of goods, services and people.

The service tunnel in which last week's breakthrough occurred lies between two larger railroad tunnels, not as close to completion, through which Chunnel traffic will be carried. By the year 2003, an average of 54,500 passengers on the vehicle shuttles and 67,670 passengers on the railway trains are forecast to transit the tunnel daily. The vehicles will be carried on shuttle trains initially running at least every 15 minutes at peak periods and making the crossing in 35 minutes. Alternating will be passenger trains, while freight will trundle through in off-peak hours. For motorists, travel time between Paris and London will shrink somewhat, but for rail passengers the ride will be cut from 12 hours to three. The Chunnel will make rail and air roughly comparable in terms of the clock, if time spent getting to and from airports is counted.

On the French side, the project has served as a magnet, attracting high- velocity rail lines and new highways that will speed travelers from Britain into Europe's expanding transport network. By contrast, residents of Britain's prosperous rural Kent have opposed construction and the industrialization that will follow. British road and rail systems -- which include no high-speed equipment -- remain inadequate. Thatcher's government spends only a fraction of France's commitment to improving infrastructure. Many businessmen fear that Britain's failure to take full advantage of the Chunnel link will not make it easier for them to compete in the new Europe.

But the problem goes deeper. Last week, when news of the Chunnel breakthrough was announced, the Sun, Britain's leading tabloid, cautioned its readers, "It won't be long before the garlic-breathed bastilles will be here in droves once the Channel Tunnel is open." Deep in the British psyche there is a conservatism about ending the island-nation status. Labour Party transport spokesman John Prescott calls this attitude one of England's greatest problems. "We're going to have to be more reoriented toward Europe," he says. In spite of Britain's reservations, when the main breakthrough occurs on Dec. 1, men will meet, clasp hands and celebrate the fulfillment of a dream that has been alive for more than two centuries.

With reporting by Anne Constable/London and Tala Skari/Sangatte