LONDON -- 2004 marks the 100th anniversary of the Entente Cordiale -- the accord between Britain and France of 1904 that marked a new era of friendship, the ending of numerous disputes and, as it turned out, intimate military alliance in two world wars.

Yet despite these heroic moments of the 20th century, it would be difficult to find a relationship between two nations that was more ambiguous, more full of contradictions, more conducive of hypocrisy and more prone to shifts of mood than the British-French one.

The situation here and now is a perfect example of all these characteristics. To mark the centenary, London is staging numerous events and exhibitions to prove just how much the British love all things French. French President Jacques Chirac is to visit London and will address both Houses of Parliament.

Yet, at the same time, French policy toward European integration and the Atlantic alliance continues to cause deep irritation in London since the French never tire of hinting that they regard Britain as much too close to the United States and that the British are not really suitable candidates for the "inner core" of European nations dedicated to building a counterweight to American hegemony.

This leaves the British policy hovering uneasily between the desire to remain America's "best ally" and the desire to keep in with the largest players in the European Union, namely France and Germany.

This in turn is leading to extraordinary convolutions, with British Prime Minister Tony Blair telling the French he is right behind them in building up European defenses on an autonomous basis, with a separate operational command structure from the North Atlantic Treaty Organization, while telling the Americans in Washington that nothing is being, or will be done, to undermine NATO. Everyone knows that the French are determined to do NATO down so the two postures simply do not add up. But the pretense continues.

The tricky task of being friendly both with Paris and with Washington is leading British policy into potentially dangerous waters. At the very moment that French leaders are talking about forming an inner grouping of European countries that would exclude Britain, the policymakers are also talking about France, Britain and Germany getting together in a triumvirate, or directorate, to "steer" -- i.e., dominate -- the EU. Such a course is only "logical," says British Foreign Secretary Jack Straw.

Logicality in national affairs is a French specialty and British officials should be wary of projects bearing that label. Not only would this move fatally weaken Anglo-American links -- and some say that disillusion with Blair is already setting in among American officials -- but it would lead the British into another disastrous European policy error. Far from being seen to side so heavily with France and Germany in a "Big Three" club, a skilled British government should be bending over backward to work with, and perhaps lead, the smaller and newer member states of the Union, especially the 10 from East and central Europe who will join May 1.

These smaller countries look with alarm at the dictatorial tone of pronouncements from Paris and long for the British to take a more balanced lead in favor of their interests. Such a course would lead to a far more comfortable and unified kind of enlarged Europe than the present Franco-centric trends.

The French and British attitudes toward each other contain many other ironies. The French think they are the "fast track" Europeans, and the British, along with the Danes, are the laggards. In reality, as European Commission officials keep pointing out, it is France that is far the slowest member state at implementing European laws, while both France and Germany are the slow growth economies of the Union, in contrast to those on the edges, such as Britain, Scandinavia and Central Europe, who are Europe's true dynamos.

Then there is the enlargement aim itself, which the British strongly support but to which France is increasingly hostile, with French Minister for Europe Noelle Lenoir going so far as to say that a union of 25 members is "too big to be organized as one unit."

Those who take a long and historical view would simply shrug their shoulders and say there is nothing new in this mass of contradictions and constantly shifting positions. A hundred years ago it was France that was America's best friend and the British "imperialists" whom Washington regarded with suspicion. When American troops first arrived in France in 1917, they refused to fight alongside Britain and insisted on working with the French.

Today U.S. antagonism toward France is undisguised, as instanced by the American refusal to allow French contractors to take work in Iraq, and by their belief, probably correct, that France is opposed to the entire American policy toward the Middle East and toward the war on terrorism generally, while the British remain staunch supporters -- one more puzzling twist in the complex skein of London-Paris relations.

None of this is going to mar the celebrations of cultural togetherness at the entente's centenary. Neither country can exist without the other, whatever the policy clashes. As it has done for the last thousand years, in a cycle of war and peace, love and hate, admiration and distaste, the British-French relationship will carry on -- not just for another hundred years but indefinitely.