LONDON — BRITAIN and France have begun to build a new entente cordiale, or friendly relationship, and they are using their possession of nuclear weapons as a cornerstone of the partnership.
At a summit meeting this week notable for the warmth of their words and body language, British Prime Minister John Major and French President Jacques Chirac committed their governments to a nuclear weapons pact based on Britain's independent deterrent and France's force de frappe.
They also agreed to develop conventional military equipment in tandem and to cooperate closely in the air defense of northern Europe.
As Chirac addressed a beaming Major as ''mon cher John'' and the British prime minister spoke of their two nations forging a ''global partnership,'' it became clear why the London government has resolutely refused to condemn French nuclear testing on the Mururoa Atoll in the South Pacific.
''Britain and France have an identity of interest in the nuclear field, and we believe the French had a right to decide that they needed to carry out a test program at Mururoa,'' said a British defense official.
At a news conference after their two-day meeting the two leaders spoke of their considerable convergence on nuclear doctrine and policy, with Chirac noting that he could not foresee a conflict where France and Britain would be on different sides.
Such friendship between the two neighbors separated by the English Channel and sharply different languages is far from routine. France under President Charles de Gaulle kept Britain out of the European Union for several years, and under President Francois Mitterrand it was always obvious that ties with the German government in Bonn were far more important than the relationship with London.
Both countries' possession of nuclear weapons, however, has indicated an identity of interest in defense. There have been persistent, though unconfirmed reports, that France will give Britain access to results of its Mururoa tests.
It has been known for some time that devising suitable new warheads for both the French and British nuclear fleets has posed problems, and it seems probable that it is in this area that they have agreed to exchange information.
But Major and Chirac suggested that the partnership they are determined to build will extend far beyond defense matters. In their joint statement after the summit held at the British leader's country home, Chequers, they said their governments would cooperate more closely on combatting terrorism and the international traffic in drugs.
Unlike other members of the European Union, Britain and France have been reluctant to open their frontiers to the free movement of people lest this encourage terrorism and the spread of narcotics.
To underline their wish for their countries to achieve a closer relationship, Major and Chirac agreed to establish a student exchange scheme patterned on the Rhodes Scholarships, which enable students from America and other countries to study at Oxford University.
Entente Cordiale Scholarships each year will be offered initially to 40 students from each country, with the number rising eventually to 200. The Entente Cordiale was an agreement struck in 1904 between Britain and France that was the basis of the two countries' opposition to German aggression 10 years later.
Major's obvious delight at having developed a warm relationship with Chirac has prompted warnings in the British media that the friendship may have limits.
The Financial Times said Tuesday that France will always rate its relations with Germany as more important than any friendship that may be forged with Britain. ''The [French] president's long-term vision for Europe remains different to that of Mr. Major,'' the paper said. ''Good personal chemistry between Mr. Major and Mr. Chirac will not change that.''
It's clear why John Major never condemned French nuclear testing in the South Pacific: Britain may receive the test results.