France returns to the heart of Nato's defence

France will announce today that it is to move back to the heart of Nato by rejoining the alliance's Defence Planning Committee, which it left in 1966.

The move marks a major boost for the credibility of Nato as it embarks on its biggest operation ever, sending 60,000 troops to police the peace in Bosnia. France will announce its decision at a symbolic meeting of Nato's defence and foreign ministers in Brussels, who are gathering to endorse the Dayton peace agreement and finalise details of the peace implementation force.

President Jacques Chirac of France is believed to have been considering French relations with Nato for several months, and to have made his decision after intensive discussions with President Bill Clinton. The need for better co-ordination on the ground in Bosnia is believed to be the main reason for Mr Chirac's new readiness to take France back into the Defence Planning Committee, as well as Nato's Military Committee.

Although France has always taken part in Nato's political decisions, its exclusion from defence and military planning has meant its forces have been co-ordinated on an ad hoc basis. From now on, French defence ministers will be present when military strategy is drawn up at Nato headquarters.

France has so far not taken the decision, however, to join Nato's full integrated military command structure. This would involve designating forces for future Nato operations in advance, and sending French officers to Nato command centres. Following today's move, however, Mr Chirac is shortly expected to announce a full return to Nato's military structure.

British officials last night welcomed the decision, which they said had been taken in full consultation with the other Nato allies. "This represents a gradual reappraisal by the French of the changing role of Nato, and shows that France is changing too," said a British source. "France also appears to have learned from the practice of co-operation with other forces on the ground in Bosnia."

It was General de Gaulle who took France out of Nato's defence planning in 1966, partly due to concern at US domination within the alliance, and partly as a statement of French independence. The difficulties of isolation were highlighted by the Bosnian experience, and could have made the situation impossible once French forces begin policing Sarajevo as part of the peace implementation force. Countries on the Defence Planning Committee draw up shared defence objectives, agree shared goals and pass on information about their forces, while the French have taken part in operations only on their own terms.

Francois Mitterrand, the former French president, was reluctant to recommit the country to Nato at a time when the future of the alliance seemed in doubt. After the end of the Cold War it was widely predicted that Nato had served its purpose, and calls mounted for Europe to develop its own defence arm, centring on the Western European Union and answerable to the European Union. However, the Europeans have failed to make convincing progress.